Quasi-zero-stiffness passive vibration isolation platform

Abstract

A quasi-zero stiffness passive vibration isolation table is beneficial to solving the problems that an existing vibration isolation table is high in inherent frequency, quasi-zero stiffness is difficult to adjust and the vibration isolation effect is poor, and is characterized by comprising a vertical vibration isolator and a horizontal vibration isolator which are arranged below a load platform and are both located in a supporting seat, and the vertical vibration isolator and the horizontal vibration isolator are arranged in the supporting seat. A vertical negative stiffness mechanism is arranged in the vertical vibration isolator, the vertical negative stiffness mechanism is provided with a lateral adjusting mechanism, the load platform is used for placing an object to be subjected to vibration isolation, the vertical vibration isolator and the horizontal vibration isolator are fixedly connected through a ball joint in an inverted swinging mode, and the supporting seat is connected with a foundation.

Description

Technical Field

[0001] The invention belongs to the technical field of precision vibration isolation, and in particular relates to a quasi-zero stiffness passive vibration isolation table. Background Art

[0002] With the continuous improvement of the precision of precision measuring instruments and precision processing and manufacturing equipment, the environmental requirements of equipment for micro-vibration have risen sharply, especially for the interference suppression of low-frequency vibration. The passive vibration isolation table reduces the transmission of vibration to the isolated object by reasonably setting mechanical structures such as springs and damping. It has the characteristics of simple structure and high reliability, and can isolate frequencies greater than the natural frequency of the vibration isolation table. times the vibration interference. To achieve the suppression of ultra-low frequency vibration, it is necessary to further reduce the natural frequency of the vibration isolation system. Quasi-zero stiffness vibration isolation is an effective solution. By connecting the negative stiffness mechanism and the positive stiffness element in parallel, quasi-zero stiffness is obtained at the static equilibrium position, which greatly reduces the natural frequency of the vibration isolation system, thus having ultra-low frequency vibration isolation characteristics.

[0003] Existing quasi-zero stiffness isolators have a small working range and are often limited to a single load. Once the isolator is manufactured, the structural parameters are difficult to change, and it is obviously unable to meet the vibration isolation requirements of different objects. Some adjustable quasi-zero stiffness isolators have multiple levels of stiffness, but they can only have quasi-zero stiffness characteristics for loads of a few specific masses, and cannot achieve continuous changes in stiffness. Therefore, designing a passive vibration isolation table with continuously adjustable quasi-zero stiffness is one of the key issues that need to be solved in this field. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a quasi-zero stiffness passive vibration isolation table, which is conducive to solving the problems of high natural frequency, difficult to adjust quasi-zero stiffness and poor vibration isolation effect of the existing vibration isolation table.

[0005] The technical solution of the present invention is as follows:

[0006] A quasi-zero stiffness passive vibration isolation table is characterized in that it includes a vertical vibration isolator and a horizontal vibration isolator arranged below the load platform, the vertical vibration isolator and the horizontal vibration isolator are both located in a support seat, the vertical vibration isolator has a vertical negative stiffness mechanism, the vertical negative stiffness mechanism has a lateral adjustment mechanism, the load platform is used to place the vibration-isolated object, the vertical vibration isolator and the horizontal vibration isolator are fixedly connected by a ball joint inverted pendulum, and the support seat is connected to the foundation.

[0007] The upper end of the ball joint inverted pendulum (33) is connected to the horizontal vibration isolation platform (31) of the horizontal vibration isolator (3), and the lower end of the ball joint inverted pendulum (33) is connected to the lower bearing platform (213) of the vertical vibration isolator. The ball joint inverted pendulum (33) rotates circumferentially within a certain range to provide horizontal negative stiffness. Horizontal springs (32) are hung between the two corresponding side surfaces of the horizontal vibration isolation platform (3) and the upper bearing platform (211) of the vertical vibration isolator (2). The horizontal springs that balance the displacement in the x-axis direction and the horizontal springs that balance the displacement in the y-axis direction jointly provide horizontal positive stiffness. Quasi-zero stiffness passive vibration isolation is achieved by balancing the horizontal positive stiffness and the horizontal negative stiffness.

[0008] Include the following expressions:

[0009]

[0010] Where K is the dimensionless equivalent stiffness of the horizontal vibration isolator, x is the deformation of the horizontal spring, h is the height from the horizontal spring to the bottom of the ball joint pendulum, k is the total stiffness of the horizontal spring, m is the load mass, g is the acceleration of gravity, and H is the length of the ball joint pendulum.

[0011] The vertical vibration isolator (2) comprises a bearing mechanism (21), a vertical spring (22), a vertical negative stiffness mechanism (23), and a load adjustment mechanism (24), wherein the bearing mechanism (21) comprises an upper bearing platform (211), a connecting rod A (212), and a lower bearing platform (213), the upper bearing platform (211) and the lower bearing platform (213) are fixedly connected via the connecting rod A (212), the upper end of the vertical spring (22) is fixedly connected to the upper bearing platform (211), and the lower end is fixedly connected to a spring tray C (245), the vertical spring (22) is used to bear the load and provide positive stiffness in the vertical direction, and the vertical negative stiffness mechanism (23) can adjust the negative stiffness to achieve quasi-zero stiffness.

[0012] The vertical negative stiffness mechanism (23) comprises a guide rail (231), a slider (232), a rotating connecting rod (233), a support (234) and a lateral adjustment mechanism (235), and is basically symmetrical on the left and right. The guide rail (231) is fixedly connected to the support base plate (41) via a connecting rod B (236); the slider (232) can slide linearly along the guide rail (231); the rotating connecting rod (233) is rotatably connected to the slider (232) and the support (234) respectively; the support (234) is fixedly connected to the lower bearing platform (213) via a connecting rod C (237); the lateral adjustment mechanism adjusts the vertical negative stiffness by moving the slider (232) and changing the angle between the rotating connecting rod (233) and the horizontal plane.

[0013] The lateral adjustment mechanism (235) comprises a lateral spring (2351), a screw rod A (2352), a screw rod B (2353), a spring tray A (2354) and a spring tray B (2355), wherein two ends of the lateral spring (2351) are fixedly connected to the spring tray A (2354) and the spring tray B (2355); the screw rod A (2352) sequentially penetrates the spring tray A (2354), the lateral spring (2351), the spring tray B (2355) and the slider (232), and the other side sequentially penetrates in the opposite direction; the spring tray A (2354) is threadedly connected to the screw rod A (2352) and fixedly connected to the screw rod B; the spring tray B (2355) is threadedly connected to the screw rod B (2353) and fixedly connected to the slider (232).

[0014] The load adjustment mechanism (24) comprises an indicator (241), a worm (242), a turbine (243), a screw C (244) and a spring tray C (245), wherein the indicator (241) is fixedly connected to the side of the upper bearing platform (211), the screw C (244) passes through the supporting bottom plate (41) and is fixedly connected to the center of the turbine (243), and the spring tray C (245) is threadedly connected to the screw C (244). The spring tray C (245) moves up and down in the vertical direction through the worm and worm structure.

[0015] The support seat (4) comprises a support base plate (41), a support side plate (42), a support foot (43) and an outer shell (44), wherein the support side plate (42) is a main frame, and the support base plate (41), the support foot (43) and the outer shell (44) are all fixedly connected to the support side plate (42); the connecting rod A (212) and the connecting rod C (237) pass through the support base plate (41), and the support foot (43) is placed on a horizontal ground.

[0016] The supporting side plate (42) is provided with a vertical through hole A (421), and the limiting rod (34) can swing slightly in the through hole A (421) to prevent the ball joint from swinging backwards and becoming unstable; the outer shell is provided with a horizontal through hole B (441) and a through hole C (442), the worm (242) passes through the through hole B (441), and the indicator (241) can move slightly in the through hole C (442).

[0017] By adjusting the worm (242), the indicator (241) can be located at the center of the through hole C (442).

[0018] The technical effects of the present invention are as follows:

[0019] 1. The present invention is suitable for ultra-low frequency vibration isolation of different loads. The vertical and horizontal stiffness can be adjusted according to the load mass to obtain quasi-zero characteristics, so that the natural frequency of the vibration isolation table is greatly reduced, and ultra-low frequency vibration isolation is achieved;

[0020] 2. The present invention is provided with a vertical vibration isolator, and a vertical negative stiffness mechanism is formed by using components such as a slider and a connecting rod, and the negative stiffness is easily adjusted through a lateral adjustment mechanism, and at the same time, quasi-zero stiffness is achieved in parallel with a vertical spring;

[0021] 3. The present invention is provided with a horizontal vibration isolator, which realizes a quasi-zero characteristic in the horizontal direction by flexibly adjusting the positive stiffness of the horizontal spring and combining it with the inverted pendulum of the ball joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the quasi-zero stiffness passive vibration isolation platform of the present invention.

[0023] Figure 2 for Figure 1 Schematic diagram of the vertical vibration isolator structure.

[0024] Figure 3 for Figure 2 Schematic diagram of the vertical negative stiffness mechanism structure.

[0025] Figure 4 for Figure 3 Schematic diagram of the lateral adjustment mechanism structure.

[0026] Figure 5 for Figure 1 Schematic diagram of the horizontal vibration isolator structure.

[0027] Figure 6 for Figure 1 Schematic diagram of the support base structure.

[0028] The reference numerals are listed as follows: 1-load platform; 2-vertical vibration isolator; 3-horizontal vibration isolator; 4-support seat; 22-vertical spring; 23-vertical negative stiffness mechanism; 211-upper bearing platform; 212-connecting rod; 213-lower bearing platform (211, 212, 213 constitute a bearing mechanism); 231-guide rail; 232-slider; 233-rotating connecting rod; 234-support; 235-lateral adjustment mechanism; 236-connecting rod B; 237-connecting rod C; 2351-lateral spring; 2352-screw A; 2353-screw B ; 2354-spring tray A; 2355-spring tray B; 241-indicator; 242-worm; 243-turbine; 244-stud C; 245-spring tray C (241, 242, 243, 244, 245 constitute a load adjustment mechanism); 31-horizontal vibration isolation platform; 311-vibration isolation pad; 32-horizontal spring; 33-ball joint inverted swing; 34-limiting rod; 41-support base plate; 42-support side plate; 43-support foot; 44-housing; 421-through hole A; 441-through hole B; 442-through hole C. DETAILED DESCRIPTION

[0029] Below is the attached figure ( Figure 1-Figure 6 ) and Examples illustrate the present invention.

[0030] Figure 1 It is a structural schematic diagram of the quasi-zero stiffness passive vibration isolation platform of the present invention. Figure 2 for Figure 1 Schematic diagram of the vertical vibration isolator structure. Figure 3 for Figure 2 Schematic diagram of the vertical negative stiffness mechanism structure. Figure 4 for Figure 3 Schematic diagram of the lateral adjustment mechanism structure.

[0031] Figure 5 for Figure 1 Schematic diagram of the horizontal vibration isolator structure. Figure 6 for Figure 1 Schematic diagram of the support structure in . Figures 1 to 6 As shown, a quasi-zero stiffness passive vibration isolation table includes a vertical vibration isolator and a horizontal vibration isolator arranged below a load platform, wherein the vertical vibration isolator and the horizontal vibration isolator are both located in a support seat, wherein the vertical vibration isolator has a vertical negative stiffness mechanism, wherein the vertical negative stiffness mechanism has a lateral adjustment mechanism, wherein the load platform is used for placing an object to be isolated, wherein the vertical vibration isolator is fixedly connected to the horizontal vibration isolator by an inverted pendulum ball joint, and wherein the support seat is connected to a foundation. The upper end of the ball joint inverted pendulum (33) is connected to the horizontal vibration isolation platform (31) of the horizontal vibration isolator (3), and the lower end of the ball joint inverted pendulum (33) is connected to the lower bearing platform (213) of the vertical vibration isolator. The ball joint inverted pendulum (33) rotates circumferentially within a certain range to provide horizontal negative stiffness. Horizontal springs (32) are hung between the two corresponding side surfaces of the horizontal vibration isolation platform (3) and the upper bearing platform (211) of the vertical vibration isolator (2). The horizontal springs that balance the displacement in the x-axis direction and the horizontal springs that balance the displacement in the y-axis direction jointly provide horizontal positive stiffness. Quasi-zero stiffness passive vibration isolation is achieved by balancing the horizontal positive stiffness and the horizontal negative stiffness.

[0032] Include the following expressions:

[0033]

[0034] Where K is the dimensionless equivalent stiffness of the horizontal vibration isolator, x is the deformation of the horizontal spring, h is the height from the horizontal spring to the bottom of the ball joint pendulum, k is the total stiffness of the horizontal spring, m is the load mass, g is the acceleration of gravity, and H is the length of the ball joint pendulum.

[0035] The vertical vibration isolator (2) comprises a bearing mechanism (21), a vertical spring (22), a vertical negative stiffness mechanism (23), and a load adjustment mechanism (24), wherein the bearing mechanism (21) comprises an upper bearing platform (211), a connecting rod A (212), and a lower bearing platform (213), the upper bearing platform (211) and the lower bearing platform (213) are fixedly connected via the connecting rod A (212), the upper end of the vertical spring (22) is fixedly connected to the upper bearing platform (211), and the lower end is fixedly connected to a spring tray C (245), the vertical spring (22) is used to bear the load and provide positive stiffness in the vertical direction, and the vertical negative stiffness mechanism (23) can adjust the negative stiffness to achieve quasi-zero stiffness. The vertical negative stiffness mechanism (23) comprises a guide rail (231), a slider (232), a rotating connecting rod (233), a support (234) and a lateral adjustment mechanism (235), which are basically symmetrical. The guide rail (231) is fixedly connected to the support base plate (41) through a connecting rod B (236); the slider (232) can slide linearly along the guide rail (231); the rotating connecting rod (233) is rotatably connected to the slider (232) and the support (234) respectively; the support (234) is fixedly connected to the lower bearing platform (213) through a connecting rod C (237). The lateral adjustment mechanism adjusts the vertical negative stiffness by moving the slider (232) and changing the angle between the rotating connecting rod (233) and the horizontal plane.

[0036] The lateral adjustment mechanism (235) comprises a lateral spring (2351), a screw rod A (2352), a screw rod B (2353), a spring tray A (2354) and a spring tray B (2355), wherein two ends of the lateral spring (2351) are fixedly connected to the spring tray A (2354) and the spring tray B (2355); the screw rod A (2352) sequentially penetrates the spring tray A (2354), the lateral spring (2351), the spring tray B (2355) and the slider (232), and the other side sequentially penetrates in the opposite direction; the spring tray A (2354) is threadedly connected to the screw rod A (2352) and fixedly connected to the screw rod B; the spring tray B (2355) is threadedly connected to the screw rod B (2353) and fixedly connected to the slider (232). The load adjustment mechanism (24) comprises an indicator (241), a worm (242), a turbine (243), a screw C (244) and a spring tray C (245), wherein the indicator (241) is fixedly connected to the side of the upper bearing platform (211), the screw C (244) passes through the supporting bottom plate (41) and is fixedly connected to the center of the turbine (243), and the spring tray C (245) is threadedly connected to the screw C (244). The spring tray C (245) moves up and down in the vertical direction through the worm and worm structure.

[0037] The support seat (4) comprises a support base plate (41), a support side plate (42), a support foot (43) and a shell (44), wherein the support side plate (42) is a main frame, and the support base plate (41), the support foot (43) and the shell (44) are all fixedly connected to the support side plate (42); the connecting rod A (212) and the connecting rod C (237) penetrate the support base plate (41), and the support foot (43) is placed on a horizontal ground. The support side plate (42) is provided with a vertical through hole A (421), and the limit rod (34) can swing slightly in the through hole A (421) to prevent the ball joint from inverting and becoming unstable; the shell is provided with a horizontal through hole B (441) and a through hole C (442), the worm (242) penetrates the through hole B (441), and the indicator (241) can move slightly in the through hole C (442). By adjusting the worm (242), the indicator (241) can be located at the center of the through hole C (442).

[0038] The present invention discloses a quasi-zero stiffness passive vibration isolation platform, comprising: a load platform, a support seat, a vertical vibration isolator and a horizontal vibration isolator. The vertical vibration isolator comprises a vertical negative stiffness mechanism with adjustable quasi-zero stiffness and a vertical spring, and the horizontal vibration isolator comprises a horizontal spring with adjustable quasi-zero stiffness and a ball joint inverted pendulum. The present invention can flexibly adjust the horizontal positive stiffness and the vertical negative stiffness according to the load mass, so that the system has a quasi-zero stiffness characteristic, thereby realizing ultra-low frequency passive vibration isolation.

[0039] like Figure 1 As shown, the quasi-zero stiffness passive vibration isolation platform of the present invention comprises a load platform (1), a vertical vibration isolator (2), a horizontal vibration isolator (3) and a support seat (4). It is characterized in that the load platform (1) is placed on the upper layer of the horizontal vibration isolator (3) for placing the object to be isolated; the vertical vibration isolator (2) and the horizontal vibration isolator (3) are fixedly connected by a ball joint inverted pendulum (34); and the support seat is connected to the foundation. The present invention can flexibly adjust the horizontal positive stiffness and the vertical negative stiffness according to the load mass, so that the system has a quasi-zero stiffness characteristic and realizes ultra-low frequency passive vibration isolation.

[0040] like Figure 2 As shown, the vertical vibration isolator (2) includes a bearing mechanism (21), a vertical spring (22), a vertical negative stiffness mechanism (23), and a load adjustment mechanism (24), wherein the bearing mechanism (21) includes an upper bearing platform (211), a connecting rod A (212), and a lower bearing platform (213), and the upper bearing platform (211) and the lower bearing platform (213) are fixedly connected via the connecting rod A (212). The upper end of the vertical spring (22) is fixedly connected to the upper bearing platform (211), and the lower end is fixedly connected to the spring tray C (245). The vertical spring (22) is used to bear the load and provide positive stiffness in the vertical direction. The vertical negative stiffness mechanism (23) can adjust the negative stiffness to achieve quasi-zero stiffness.

[0041] like Figure 3As shown, the vertical negative stiffness mechanism (23) includes a guide rail (231), a slider (232), a rotating connecting rod (233), a support (234) and a lateral adjustment mechanism (235), which are basically symmetrical. The guide rail (231) is fixedly connected to the support base plate (41) through a connecting rod B (236); the slider (232) can slide linearly along the guide rail (231); the rotating connecting rod (233) is rotatably connected to the slider (232) and the support (234) respectively; the support (234) is fixedly connected to the lower bearing platform (213) through a connecting rod C (237). The lateral adjustment mechanism adjusts the vertical negative stiffness by moving the slider (232) and changing the angle between the rotating connecting rod (233) and the horizontal plane.

[0042] The load adjustment mechanism (24) comprises an indicator (241), a worm (242), a turbine (243), a screw C (244) and a spring tray C (245), wherein the indicator (241) is fixedly connected to the side of the upper bearing platform (211), the screw C (244) passes through the supporting bottom plate (41) and is fixedly connected to the center of the turbine (243), and the spring tray C (245) is threadedly connected to the screw C (244). The spring tray C (245) moves up and down in the vertical direction through the worm and worm structure.

[0043] like Figure 4 As shown, the lateral adjustment mechanism (235) includes a lateral spring (2351), a screw rod A (2352), a screw rod B (2353), a spring tray A (2354) and a spring tray B (2355), wherein the two ends of the lateral spring (2351) are fixedly connected to the spring tray A (2354) and the spring tray B (2355); the screw rod A (2352) sequentially penetrates the spring tray A (2354), the lateral spring (2351), the spring tray B (2355) and the slider (232), and the other side penetrates in reverse order; the spring tray A (2354) is threadedly connected to the screw rod A (2352) and fixedly connected to the screw rod B; the spring tray B (2355) is threadedly connected to the screw rod B (2353) and fixedly connected to the slider (232).

[0044] like Figure 5 As shown, the horizontal vibration isolator (3) includes a horizontal vibration isolation platform (31), a horizontal spring (32), a ball joint pendulum (33) and a limit rod (34). A vibration isolation pad (311) is installed on the upper surface of the horizontal vibration isolation platform (31) to prevent the load from tilting; the upper end of the ball joint pendulum (33) is connected to the horizontal vibration isolation platform (31), and the lower end is connected to the lower bearing platform (213), and rotates circumferentially within a certain range to provide horizontal negative stiffness; horizontal vibration isolation platform (31) and upper bearing platform (211) are hung on each side surface with horizontal springs (32) to provide horizontal positive stiffness, and the quasi-zero stiffness of the horizontal vibration isolator is achieved by selecting horizontal springs with appropriate stiffness.

[0045] like Figure 6 As shown, the support seat (4) includes a support base plate (41), a support side plate (42), a support foot (43) and a shell (44). The support side plate (42) is the main frame, and the support base plate (41), the support foot (43) and the shell (44) are all fixedly connected to the support side plate (42); the connecting rod A (212) and the connecting rod C (237) pass through the support base plate (41); and the support foot (43) is placed on the horizontal ground. The support side plate (42) is provided with a vertical through hole A (421), and the limit rod (34) can swing slightly in the through hole A (421) to prevent the ball joint from swinging backwards and becoming unstable; the shell is provided with a horizontal through hole B (441) and a through hole C (442), and the worm (242) passes through the through hole B (441), and the indicator (241) can move slightly in the through hole C (442). By adjusting the worm (242), the indicator (241) can be located at the center of the through hole C (442).

[0046] A load with a mass of m is placed on the load platform, and according to the force transmission effect, the horizontal vibration isolation platform (31), the lower bearing platform (213), the connecting rod A (212), the upper bearing platform (211), and the indicator (241) all move downward. If the load mass is too small, the indicator (241) is located above the center of the through hole C (442); otherwise, it is located below the center.

[0047] For a static load m, the stiffness is k z The compression amount Δx of the vertical spring (22) is constant, which is The worm (243) is rotated, and the worm gear structure transmits the motion to the screw C (244). Further, the rotation of the screw C causes the spring tray C (245) to move up and down in the vertical direction. Since the compression amount Δx of the vertical spring (22) is constant, the vertical spring (22), the upper bearing platform (211), and the indicator (241) move up and down accordingly. When the indicator (241) is located at the center of the through hole C (422), it means that the load size is appropriate.

[0048] By rotating screw A (2352), spring tray A (2354) and screw B (2353) move left and right in the horizontal direction, and further transmit the movement to spring tray B (2355) and slider (232). The movement of slider (232) along guide rail (231) changes the angle between rotating connecting rod (233) and the horizontal plane, thereby causing support (234) to move vertically, and transmitting the force to lower bearing platform (213) through connecting rod C (237), thereby realizing the adjustment of negative stiffness.

[0049] The dimensionless equivalent stiffness K of the horizontal vibration isolator is: Where x is the horizontal spring deformation, h is the height from the horizontal spring to the bottom of the ball joint pendulum, k is the total stiffness of the horizontal spring, m is the load mass, g is the gravity acceleration, and H is the length of the ball joint pendulum. By designing reasonable structural parameters h and H, the stiffness k of the horizontal spring is adjusted to meet Quasi-zero stiffness can be achieved.

[0050] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "circumferential" and the like indicate orientations or positional relationships 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, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0051] The contents not described in detail in the specification of the present invention belong to the prior art known to the professional and technical personnel in the field. It is pointed out here that the above description helps those skilled in the art to understand the invention, but does not limit the protection scope of the invention. Any equivalent replacement, modification and / or simplification of the above description without departing from the essence of the invention falls within the protection scope of the invention.

Claims

1. Quasi-zero stiffness passive vibration isolation table, characterized in that: It includes a vertical vibration isolator and a horizontal vibration isolator arranged below the load platform, both of which are located in a support seat, the vertical vibration isolator has a vertical negative stiffness mechanism, the vertical negative stiffness mechanism has a lateral adjustment mechanism, the load platform is used to place the object to be isolated, the vertical vibration isolator and the horizontal vibration isolator are fixedly connected by a ball joint inverted pendulum, and the support seat is connected to the foundation.

2. The quasi-zero stiffness passive vibration isolation table according to claim 1, characterized in that: The upper end of the ball joint inverted pendulum (33) is connected to the horizontal vibration isolation platform (31) of the horizontal vibration isolator (3), and the lower end of the ball joint inverted pendulum (33) is connected to the lower bearing platform (213) of the vertical vibration isolator. The ball joint inverted pendulum (33) rotates circumferentially within a certain range to provide horizontal negative stiffness. Horizontal springs (32) are hung between the two corresponding side surfaces of the horizontal vibration isolation platform (3) and the upper bearing platform (211) of the vertical vibration isolator (2). The horizontal springs that balance the displacement in the x-axis direction and the horizontal springs that balance the displacement in the y-axis direction jointly provide horizontal positive stiffness. Quasi-zero stiffness passive vibration isolation is achieved by balancing the horizontal positive stiffness and the horizontal negative stiffness.

3. The quasi-zero stiffness passive vibration isolation table according to claim 2, characterized in that: Include the following expressions: Where K is the dimensionless equivalent stiffness of the horizontal vibration isolator, x is the deformation of the horizontal spring, h is the height from the horizontal spring to the bottom of the ball joint pendulum, k is the total stiffness of the horizontal spring, m is the load mass, g is the acceleration of gravity, and H is the length of the ball joint pendulum.

4. The quasi-zero stiffness passive vibration isolation table according to claim 1, characterized in that: The vertical vibration isolator (2) comprises a bearing mechanism (21), a vertical spring (22), a vertical negative stiffness mechanism (23), and a load adjustment mechanism (24), wherein the bearing mechanism (21) comprises an upper bearing platform (211), a connecting rod A (212), and a lower bearing platform (213), the upper bearing platform (211) and the lower bearing platform (213) are fixedly connected via the connecting rod A (212), the upper end of the vertical spring (22) is fixedly connected to the upper bearing platform (211), and the lower end is fixedly connected to a spring tray C (245), the vertical spring (22) is used to bear the load and provide positive stiffness in the vertical direction, and the vertical negative stiffness mechanism (23) can adjust the negative stiffness to achieve quasi-zero stiffness.

5. The quasi-zero stiffness passive vibration isolation table according to claim 4, characterized in that: The vertical negative stiffness mechanism (23) comprises a guide rail (231), a slider (232), a rotating connecting rod (233), a support (234) and a lateral adjustment mechanism (235), and is basically symmetrical on the left and right. The guide rail (231) is fixedly connected to the support base plate (41) via a connecting rod B (236); the slider (232) can slide linearly along the guide rail (231); the rotating connecting rod (233) is rotatably connected to the slider (232) and the support (234) respectively; the support (234) is fixedly connected to the lower bearing platform (213) via a connecting rod C (237); the lateral adjustment mechanism adjusts the vertical negative stiffness by moving the slider (232) and changing the angle between the rotating connecting rod (233) and the horizontal plane.

6. The quasi-zero stiffness passive vibration isolation table according to claim 5, characterized in that: The lateral adjustment mechanism (235) comprises a lateral spring (2351), a screw rod A (2352), a screw rod B (2353), a spring tray A (2354) and a spring tray B (2355), wherein two ends of the lateral spring (2351) are fixedly connected to the spring tray A (2354) and the spring tray B (2355); the screw rod A (2352) sequentially penetrates the spring tray A (2354), the lateral spring (2351), the spring tray B (2355) and the slider (232), and the other side sequentially penetrates in the opposite direction; the spring tray A (2354) is threadedly connected to the screw rod A (2352) and fixedly connected to the screw rod B; the spring tray B (2355) is threadedly connected to the screw rod B (2353) and fixedly connected to the slider (232).

7. The quasi-zero stiffness passive vibration isolation table according to claim 4, characterized in that: The load adjustment mechanism (24) comprises an indicator (241), a worm (242), a turbine (243), a screw C (244) and a spring tray C (245), wherein the indicator (241) is fixedly connected to the side of the upper bearing platform (211), the screw C (244) passes through the supporting bottom plate (41) and is fixedly connected to the center of the turbine (243), and the spring tray C (245) is threadedly connected to the screw C (244). The spring tray C (245) moves up and down in the vertical direction through the worm and worm structure.

8. The quasi-zero stiffness passive vibration isolation table according to claim 1, characterized in that: The support seat (4) comprises a support base plate (41), a support side plate (42), a support foot (43) and an outer shell (44), wherein the support side plate (42) is a main frame, and the support base plate (41), the support foot (43) and the outer shell (44) are all fixedly connected to the support side plate (42); the connecting rod A (212) and the connecting rod C (237) pass through the support base plate (41), and the support foot (43) is placed on a horizontal ground.

9. The quasi-zero stiffness passive vibration isolation table according to claim 8, characterized in that: The supporting side plate (42) is provided with a vertical through hole A (421), and the limiting rod (34) can swing slightly in the through hole A (421) to prevent the ball joint from swinging backwards and becoming unstable; the outer shell is provided with a horizontal through hole B (441) and a through hole C (442), the worm (242) passes through the through hole B (441), and the indicator (241) can move slightly in the through hole C (442).

10. The quasi-zero stiffness passive vibration isolation table according to claim 7, characterized in that: By adjusting the worm (242), the indicator (241) can be located at the center of the through hole C (442).

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