Zero-stiffness vibration isolator

Abstract

The zero-stiffness vibration isolator comprises a carrying platform and a coil base and further comprises a main supporting spring, an upper hollow shaft, a lower hollow shaft, a magnetic negative stiffness mechanism, a cam roller mechanism and a magnetic force controller, the main supporting spring is fixedly installed between the carrying platform and the coil base, the upper hollow shaft is coaxially installed at the bottom of the carrying platform through an M3 connecting screw, and the lower hollow shaft is coaxially installed at the bottom of the coil base through an M3 connecting screw. The lower hollow shaft is coaxially arranged on the lower portion of the lower hollow shaft, the magnetic negative stiffness mechanism is arranged at the bottom of the carrying platform, the cam roller mechanism is arranged on the coil base, and the magnetic force controller is installed on the coil base. The quasi-zero stiffness vibration isolator solves the problems that in the prior art, an existing quasi-zero stiffness vibration isolator is short in vibration isolation interval, small in vibration isolation mass, poor in vibration isolation effect and low in reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of vibration reduction and isolation control, in particular to a zero-stiffness vibration isolator. Background Art

[0002] In high-end equipment manufacturing and industrial production, low-frequency vibrations, such as surface micro-vibrations and periodic vibrations in cooling systems, are a significant factor affecting production quality. In traditional vibration control, linear vibration isolation systems are limited by the "stiffness-frequency" contradiction. Specifically, the lower the system stiffness, the lower the isolation starting frequency, but the lower the load-bearing capacity, making it difficult to achieve both low-frequency vibration isolation and high static load-bearing capacity. Quasi-zero-stiffness mechanisms utilize nonlinear stiffness coupling design, such as the parallel connection of a positive-stiffness spring and a negative-stiffness mechanism, to achieve extremely low equivalent stiffness near equilibrium, surpassing the theoretical limits of linear systems.

[0003] Existing quasi-zero-stiffness isolators still have some shortcomings. First, the negative stiffness mechanism provides a narrow linear range and low stiffness, which cannot meet the requirements of large amplitudes and large vibration isolation masses. Second, for general quasi-zero-stiffness isolators, their vibration isolation effect is not perfect and does not achieve the ideal "zero stiffness". The system has low-frequency resonance, which makes the overall system robustness low. Finally, the existing passive and active control methods of quasi-zero-stiffness isolators suffer from high energy consumption, which makes their practical application difficult. Summary of the Invention

[0004] (1) Technical problems solved

[0005] In view of the shortcomings of the existing technology, the present invention provides a zero-stiffness vibration isolator to solve the problems raised in the background technology that the existing quasi-zero-stiffness vibration isolator is difficult to achieve zero stiffness, has a short vibration isolation range, small vibration isolation quality, poor vibration isolation effect, and low reliability.

[0006] (2) Technical solution

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] Zero-stiffness vibration isolators, including a loading platform and coil base, also include:

[0009] A main support spring, the main support spring being fixedly mounted between the loading platform and the coil base;

[0010] An upper hollow shaft, the upper hollow shaft being coaxially mounted on the bottom of the loading platform via an M3 connecting screw;

[0011] a lower hollow shaft, the lower hollow shaft being coaxially arranged at the lower portion of the lower hollow shaft;

[0012] A magnetic negative stiffness mechanism, which is arranged at the bottom of the loading platform and is used to provide a negative stiffness interval with high-order nonlinearity;

[0013] a cam roller mechanism, the cam roller mechanism being arranged on the coil base and being used for correcting the residual nonlinear force;

[0014] A magnetic force controller is mounted on the coil base and is used to fine-tune the residual wave force and the external disturbance response.

[0015] On the basis of the above solution, the magnetic negative stiffness mechanism includes:

[0016] An outer ring magnet, wherein three outer ring magnets are coaxially arranged, the three outer ring magnets have the same thickness, an outer magnet spacer ring is provided between every two adjacent outer ring magnets, the three outer ring magnets are coaxially arranged with the upper hollow shaft, the upper outer ring magnet is rigidly connected to the upper hollow shaft, and the lower outer ring magnet is rigidly connected to the lower hollow shaft;

[0017] Inner ring magnets, six of which are coaxially arranged, have the same thickness, and an inner magnet spacer ring is arranged between every two adjacent inner ring magnets. The six inner ring magnets are nested in the outer edge of the upper bearing frame, and the upper bearing frame is connected to the lower bearing frame through M3 connecting screws, and the lower bearing frame is connected to the coil base through M8 connecting screws.

[0018] On the basis of the above solution, the inner diameter of each inner ring magnet is coaxially arranged with the optical axis of the upper bearing frame through the shaft hole, and the inner ring magnet at the bottom is positioned by the shaft shoulder at the bottom of the optical axis of the upper bearing frame;

[0019] Upper guide bearings, three groups of upper guide bearings are rotatably mounted on the upper bearing frame via guide bearing pins, the three groups of upper guide bearings are arranged at equal angles with the axis of the upper bearing frame as the center, and each group of upper guide bearings is provided with two;

[0020] Lower guide bearings, three groups of lower guide bearings are rotatably mounted on the lower bearing frame through the guide bearing pins, the three groups of lower guide bearings are arranged at equal angles with the axis of the lower bearing frame as the center, and each group of lower guide bearings is provided with two;

[0021] Wherein, a slideway adapted to the upper guide bearing is provided on the inner side of the upper hollow shaft, and a slideway adapted to the lower guide bearing is provided on the inner side of the lower hollow shaft.

[0022] On the basis of the above solution, the cam roller mechanism includes:

[0023] The shaft sleeve frame is fixedly mounted with three shaft sleeve frames at equal angles in a circle on the coil base, and inside the shaft sleeve frame;

[0024] A movable bearing seat is slidably mounted inside each of the shaft sleeve frames;

[0025] The roller body is mounted on a movable bearing seat via a roller pin, and the movable bearing seat and the shaft sleeve frame are elastically connected via a roller support spring.

[0026] Cams, three cams are arranged at equal angles in a circular shape at the bottom of the lower hollow shaft, and the cams are connected to the lower hollow shaft through M1.2 screws. The curved surfaces of the three cams correspond one-to-one with the three roller bodies and roll against them.

[0027] Among them, the control equation of the cam surface is obtained by inverse calculation from the force-displacement curve after the positive stiffness spring compensates the magnetic negative stiffness mechanism with the first linear method, and is used to adjust the stiffness and compression of the lateral spring to perform secondary nonlinear compensation on the negative stiffness mechanism.

[0028] On the basis of the above solution, the magnetic controller includes:

[0029] Coil bodies, six of which are coaxially arranged, with a coil spacer ring fixedly installed between every two adjacent coil bodies;

[0030] A coil connecting ring is fixedly mounted on the bottom of the coil body at the lower portion, and the coil connecting ring is fixedly mounted on the coil base.

[0031] (3) Beneficial effects

[0032] Compared with the prior art, the present invention provides a zero-stiffness vibration isolator with the following beneficial effects:

[0033] 1. In the present invention, unlike the monotonically decreasing negative stiffness in traditional quasi-zero stiffness structures, the high-order nonlinearity of the magnetic negative stiffness mechanism causes its negative stiffness to first increase and then decrease, so that the negative stiffness fluctuates around a specific stiffness value within a larger displacement range, thereby increasing its effective negative stiffness range. At the same time, the introduction of high-order nonlinearity of the magnetic field reduces the distance between the dynamic and static magnets, which is conducive to maintaining the quasi-zero stiffness characteristics under large-mass bearing conditions, and effectively improving the static bearing capacity.

[0034] 2. In the present invention, the first-level linear compensation: the positive stiffness spring is connected in parallel with the magnetic negative stiffness mechanism, so that the structure generates a low-fluctuation restoring force around the zero-force axis within the working range under the action of load (such as Figure 9Secondary nonlinear compensation: The cam roller mechanism further compresses force fluctuations to ±1N through contour inversion design (matching the output force fluctuation curve); Third-level active closed-loop control: The magnetic controller only needs to fine-tune the ±1N residual fluctuation, ultimately achieving dynamic zero stiffness through multi-level force compensation accuracy.

[0035] 3. In the present invention, the multi-degree-of-freedom collaborative algorithm of the magnetic controller can compensate for disturbances such as assembly errors in real time, effectively improving the stability of the system and enhancing the anti-interference robustness.

[0036] 4. In the present invention, the active control link only needs to compensate for ±1N-level micro-force, which greatly reduces the driving power consumption and improves the energy efficiency ratio; the non-contact magnetic negative stiffness mechanism and self-lubricating ceramic slideway ensure the cycle life and achieve ultra-low energy consumption and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the overall structure of this application;

[0038] Figure 2 It is a schematic diagram of the three-dimensional structure of the cross-section in this application;

[0039] Figure 3 Schematic diagram of the cross-sectional structure of the magnetic negative stiffness mechanism in this application;

[0040] Figure 4 Schematic diagram of the polarization direction of the magnetic negative stiffness mechanism in this application;

[0041] Figure 5 Schematic diagram of the cross-sectional structure of the magnetic negative stiffness mechanism and the loading platform in this application;

[0042] Figure 6 Schematic diagram of the cross-sectional structure of the magnetic negative stiffness mechanism and the coil base in this application;

[0043] Figure 7 Schematic diagram of the cross-sectional structure of the cam roller mechanism in this application;

[0044] Figure 8 This is a schematic structural diagram of the coil base in this application;

[0045] Figure 9 Schematic diagram of the forces acting on each mechanism in this application.

[0046] In the figure: 1. Loading platform; 2. Coil base; 3. Main support spring; 4. Upper hollow shaft; 5. Lower hollow shaft; 6. Outer ring magnet; 7. Outer magnet spacer ring; 8. Inner ring magnet; 9. Inner magnet spacer ring; 10. Upper bearing frame; 11. Lower bearing frame; 12. Upper guide bearing; 13. Guide bearing pin; 14. Lower guide bearing; 15. Shaft sleeve frame; 16. Movable bearing seat; 17. Roller body; 18. Roller pin; 19. Roller support spring; 20. Cam; 21. Coil body; 22. Coil spacer ring; 23. Coil connecting ring; 24. M3 connecting screw; 25. M3 screw; 26. M8 connecting screw; 201. Roller assembly positioning platform; 202. Fixing threaded hole; 203. Hollow shaft guide column and roller through hole; 204. Lower bearing seat fixing through hole; 205. Positioning recess; 206. Coil assembly positioning countersunk hole. DETAILED DESCRIPTION

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0048] See also Figures 1 to 9 The zero-stiffness vibration isolator includes a loading platform 1 and a coil base 2, and also includes a main support spring 3, an upper hollow shaft 4, a lower hollow shaft 5, a magnetic negative stiffness mechanism, a cam roller mechanism and a magnetic controller. The main support spring 3 is fixedly installed between the loading platform 1 and the coil base 2, the upper hollow shaft 4 is coaxially installed on the bottom of the loading platform 1 through an M3 connecting screw 24, and the lower hollow shaft 5 is coaxially arranged at the lower part of the lower hollow shaft 5. The magnetic negative stiffness mechanism is arranged at the bottom of the loading platform 1 to limit the quasi-zero interval. Specifically, the magnetic negative stiffness mechanism adopts a coaxial double-ring magnetic circuit design, which consists of an outer ring magnet 6 and an outer magnet spacer ring 7 and an inner ring magnet 8 and an inner magnet spacer ring 9. It consists of a moving magnet array and a fixed magnet array. The magnetic negative stiffness mechanism includes Including outer ring magnet 6 and inner ring magnet 8, three outer ring magnets 6 are coaxially arranged, the three outer ring magnets 6 have the same thickness, an outer magnet spacer ring 7 is arranged between every two adjacent outer ring magnets 6, the three outer ring magnets 6 are coaxially arranged with the upper hollow shaft 4, the upper outer ring magnet 6 is rigidly connected to the upper hollow shaft 4, and the lower outer ring magnet 6 is rigidly connected to the lower hollow shaft 5, six inner ring magnets 8 are coaxially arranged, the six inner ring magnets 8 have the same thickness, an inner magnet spacer ring 9 is arranged between every two adjacent inner ring magnets 8, the six inner ring magnets 8 are nested in the outer edge of the upper bearing frame 10, the upper bearing frame 10 is connected to the lower bearing frame 11 by M3 screws 25, and the lower bearing frame 11 is connected to the coil base 2 by M8 connecting screws 26.

[0049] in, Figure 4 The arrow in the figure points to the polarization direction, which is from the S pole to the N pole.

[0050] in, Figure 9 A schematic diagram of the restoring forces provided by various parts of the structure is shown in FIG.

[0051] The above, such as Figures 2 to 6 As shown, the inner diameter of each inner ring magnet 8 is coaxially arranged with the optical axis of the upper bearing frame 10 through the axial hole, and the inner ring magnet 8 at the bottom is positioned by the shaft shoulder at the bottom of the optical axis of the upper bearing frame 10. It also includes an upper guide bearing 12 and a lower guide bearing 14. Three groups of upper guide bearings 12 are rotatably installed on the upper bearing frame 10 through the guide bearing pin 13. The three groups of upper guide bearings 12 are arranged at equal angles with the axis of the upper bearing frame 10 as the center, and each group of upper guide bearings 12 is provided with two. Three groups of lower guide bearings 14 are rotatably installed on the lower bearing frame 11 through the guide bearing pin 13. The three groups of lower guide bearings 14 are arranged at equal angles with the axis of the lower bearing frame 11 as the center, and each group of lower guide bearings 14 is provided with two. Among them, a slideway adapted to the upper guide bearing 12 is provided on the inner side of the upper hollow shaft 4, and the slideway is made of self-lubricating ceramic material. A slideway adapted to the lower guide bearing 14 is provided on the inner side of the lower hollow shaft 5.

[0052] Specifically, the benefit of the above structural features is that a slide is provided on the inner side of the upper hollow shaft 4 and the lower hollow shaft 5, and the slide is adapted to the upper guide bearing 12 and the lower guide bearing 14, maintaining the precise coaxiality of the inner ring magnet 8 and the outer ring magnet 6 during the axial stroke, effectively reducing the generation of errors (error ≤ 0.02mm), thereby effectively suppressing radial deviation and overturning torque, and ensuring the stability of the nonlinear magnetic repulsion effect.

[0053] like Figure 7 As shown, a cam roller mechanism is provided on the coil base 2 for correcting the residual nonlinear force. The cam roller mechanism includes a shaft sleeve frame 15, a movable bearing seat 16, a roller body 17 and a cam 20. Considering the limited adjustment capability of a single cam roller mechanism, three groups of cam roller mechanisms distributed in a circular array are used to make the radial resultant force of the structure zero, and the axial resultant force serves as a secondary nonlinear compensation.

[0054] Three shaft sleeve frames 15 are fixedly installed at equal angles in a circular shape on the coil base 2. Inside the shaft sleeve frames 15, a movable bearing seat 16 is slidably installed inside each shaft sleeve frame 15. The roller body 17 is installed on the movable bearing seat 16 through a roller pin 18. The movable bearing seat and the shaft sleeve frame 15 are elastically connected by a roller support spring 19. Three cams 20 are provided at equal angles in a circular shape on the bottom of the lower hollow shaft 5. The cam 20 is connected to the lower hollow shaft 5 through an M1.2 screw. The curved surfaces of the three cams 20 correspond one-to-one to the three roller bodies 17 and roll in abutment with them. Among them, the control equation of the curved surface of the cam 20 is the force-displacement curve after the positive stiffness spring compensates the magnetic negative stiffness mechanism by the first linear compensation. It is obtained by inverse calculation and is used to adjust the stiffness and compression of the curved spring to perform secondary nonlinear compensation on the negative stiffness mechanism to achieve a resultant force fluctuation of ±1N under static equilibrium.

[0055] like Figure 2 As shown, the magnetic controller is installed on the coil base 2 and is used to fine-tune the residual fluctuation. The magnetic controller includes a coil body 21 and a coil connecting ring 23. Six coil bodies 21 are coaxially arranged. A coil spacing ring 22 is fixedly installed between every two adjacent coil bodies 21. The coil connecting ring 23 is fixedly installed at the bottom of the lower coil body 21, and the coil connecting ring 23 is fixedly installed on the coil base 2.

[0056] When the vibration isolator is working, the coil body 21 also maintains a rigid connection with the inner ring magnet 8 in the magnetic negative stiffness mechanism, and has a relative displacement with the outer ring magnet 6. By controlling the magnitude of the current in each coil body 21, the force between the coil and the outer ring magnet 6 is controlled, and ultimately dynamic zero stiffness is achieved within a wide frequency band.

[0057] like Figure 8 As shown, the coil base 2 also includes a roller assembly positioning platform 201 and a fixed threaded hole 202, a hollow shaft guide column and a roller through hole 203, a lower bearing seat fixed through hole 204 and a positioning recess 205, and a coil assembly positioning countersunk hole 206, wherein the roller assembly positioning platform 201 and the fixed threaded hole 202 are used to install the shaft sleeve frame 15, the hollow shaft guide column and the roller through hole 203 are used to provide a moving space for the lower hollow shaft 5, the lower bearing seat fixed through hole 204 and the positioning recess 205 are used to provide a foundation for installing the lower bearing frame 11, and the coil assembly positioning countersunk hole 206 is used to install the coil connecting ring 23, thereby fixing the coil body 21 and the coil connecting ring 23.

[0058] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A zero-stiffness vibration isolator comprising a loading platform (1) and a coil base (2), characterized in that: Also includes: A main support spring (3), wherein the main support spring (3) is fixedly mounted between the loading platform (1) and the coil base (2); An upper hollow shaft (4), wherein the upper hollow shaft (4) is coaxially mounted on the bottom of the loading platform (1) via an M3 connecting screw (24); A lower hollow shaft (5), wherein the lower hollow shaft (5) is coaxially arranged at a lower portion of the lower hollow shaft (5); A magnetic negative stiffness mechanism, the magnetic negative stiffness mechanism being arranged at the bottom of the object carrying platform (1) and being used for providing a negative stiffness interval with high-order nonlinearity; A cam roller mechanism, the cam roller mechanism being arranged on the coil base (2) and being used for correcting the residual nonlinear force; A magnetic force controller is mounted on the coil base (2) and is used for fine-tuning residual wave power and external disturbances.

2. The quasi-zero stiffness vibration isolator according to claim 1, characterized in that: The magnetic negative stiffness mechanism comprises: An outer ring magnet (6), wherein three outer ring magnets (6) are coaxially arranged, the three outer ring magnets (6) have the same thickness, an outer magnet spacing ring (7) is arranged between every two adjacent outer ring magnets (6), the three outer ring magnets (6) are coaxially arranged with the upper hollow shaft (4), the upper outer ring magnet (6) is rigidly connected to the upper hollow shaft (4), and the lower outer ring magnet (6) is rigidly connected to the lower hollow shaft (5); An inner ring magnet (8), six of the inner ring magnets (8) are coaxially arranged, the six inner ring magnets (8) have the same thickness, an inner magnet spacing ring (9) is arranged between every two adjacent inner ring magnets (8), the six inner ring magnets (8) are nested in the outer edge of the upper bearing frame (10), the upper bearing frame (10) is connected to the lower bearing frame (11) through M3 screws (25), and the lower bearing frame (11) is connected to the coil base (2) through M8 connecting screws (26).

3. The quasi-zero stiffness vibration isolator according to claim 2, characterized in that: The inner diameter of each inner ring magnet (8) is coaxially arranged with the optical axis of the upper bearing frame (10) through an axial hole, and the inner ring magnet (8) at the bottom is positioned by a shaft shoulder at the bottom of the optical axis of the upper bearing frame (10); Upper guide bearings (12), three groups of upper guide bearings (12) are rotatably mounted on the upper bearing frame (10) via guide bearing pins (13), the three groups of upper guide bearings (12) being arranged at equal angles with the axis of the upper bearing frame (10) as the center, and each group of upper guide bearings (12) is provided with two; The lower guide bearing (14) is rotatably mounted on the lower bearing frame (11) via the guide bearing pin (13). The three groups of lower guide bearings (14) are arranged at equal angles with the axis of the lower bearing frame (11) as the center, and each group of lower guide bearings (14) is provided with two.

4. The quasi-zero stiffness vibration isolator according to claim 3, characterized in that: A slideway adapted to the upper guide bearing (12) is provided on the inner side of the upper hollow shaft (4), and a slideway adapted to the lower guide bearing (14) is provided on the inner side of the lower hollow shaft (5).

5. The zero-stiffness vibration isolator according to claim 1, characterized in that: The cam roller mechanism comprises: A shaft sleeve frame (15), three shaft sleeve frames (15) are fixedly mounted on the coil base (2) at equal angles in a circular shape, and inside the shaft sleeve frame (15); A movable bearing seat (16), wherein each of the shaft sleeve frames (15) is slidably mounted with the movable bearing seat (16); A roller body (17), wherein the roller body (17) is mounted on the movable bearing seat (16) via a roller pin (18), and the movable bearing seat (16) and the shaft sleeve frame (15) are elastically connected via a roller support spring (19); Cams (20), three cams (20) are arranged at equal angles in a circular shape at the bottom of the lower hollow shaft (5), and the cams (20) are connected to the lower hollow shaft (5) through M1.2 screws. The curved surfaces of the three cams (20) correspond one-to-one to the three roller bodies (17) and roll in contact with each other.

6. The zero-stiffness vibration isolator according to claim 5, characterized in that: The control equation of the cam (20) surface is obtained by back-calculating the force-displacement curve after the positive stiffness spring compensates the magnetic negative stiffness mechanism for a first order linearity, and is used to adjust the stiffness and compression of the curved surface spring to perform a second order nonlinear compensation on the negative stiffness mechanism.

7. The zero-stiffness vibration isolator according to claim 6, characterized in that: The magnetic controller comprises: Coil bodies (21), six of the coil bodies (21) are coaxially arranged, and a coil spacing ring (22) is fixedly installed between every two adjacent coil bodies (21); A coil connecting ring (23) is fixedly mounted on the bottom of the coil body (21) at the lower portion, and the coil connecting ring (23) is fixedly mounted on the coil base (2).

Images