Vertical seismic isolation system having long-period support characteristics

Abstract

A vertical seismic isolation system (1) having long-period support characteristics according to the present invention is a vertical seismic isolation system (1) having long-period support characteristics, on which equipment (3) to be protected from an earthquake is mounted and which is configured to, when an earthquake occurs, minimize the transfer of the vertical component of seismic vibrations to the equipment (3) to be protected. The vertical seismic isolation system (1) having long-period support characteristics according to the present invention has a compression spring disposed horizontally to, when a load is applied thereto, generate negative stiffness by a reaction force, so as to support a payload, thereby enabling long-periodization that is difficult to be achieved by a conventional device using a simple spring support mechanism.

Description

Vertical seismic isolation system with long-period support characteristics

[0001] The present invention relates to a vertical seismic isolation system having long-period support characteristics, and more specifically, to an invention that enables long-periodization, which is difficult to achieve with a conventional device using a simple spring support mechanism, by arranging a compression spring in a horizontal direction inside the vertical seismic isolation system to generate negative stiffness (minus stiffness) as a reaction force when a load is applied to the vertical seismic isolation system and thereby supporting the load.

[0002] (This patent is a patent supported by the Technology Innovation Development Project of the Ministry of SMEs and Startups (RS-2023-00269853))

[0003] In the event of an earthquake, not only the building but also important facilities installed inside it can suffer significant damage.

[0004] In particular, computer room servers, data centers, power supply units, precision medical devices, semiconductor workbenches, electro-optical equipment, precision production equipment, cultural heritage, artworks, and defense equipment can suffer serious damage even from minor impacts, so special protective measures are required.

[0005] An example of an existing vertical seismic isolation system is the building seismic isolation system, which is mainly installed on the foundation floors of buildings in Japan.

[0006] However, the building seismic isolation system had the problem that its main component was rubber, making maintenance difficult due to aging during use and increasing construction costs by about 30%.

[0007] In addition, existing building seismic isolation systems were effective against horizontal earthquakes but struggled to respond to vertical earthquakes.

[0008] Existing seismic isolation design technical standards specify that at least 50% of the horizontal component of an earthquake should be considered as the vertical component, but actual earthquake records show that a vertical component of 100% of the horizontal component is also being measured, so IEEE 344, the technical standard for seismic verification of nuclear power plant equipment, stipulates that 100% of the horizontal component should be applied as the vertical component.

[0009] In particular, electronic equipment in data centers, which are being rapidly constructed both domestically and internationally recently, is very sensitive to vibration, and it is reported that data errors occur at vibrations of 200 gal to 250 gal (Japan Vibration Technology Association).

[0010] To solve these problems, a vertical seismic isolation system is required to implement low seismic isolation so that the natural frequency is 1.0 Hz or less, and the said vertical seismic isolation system is essential to protect national disaster safety communication networks, defense facilities, semiconductor production facilities, electro-optical facilities, precision medical devices, cultural properties, artworks, etc. from earthquake disasters.

[0011] Until now, vertical seismic isolation systems consisting of existing vertical springs installed at the bottom of protected facilities have sought ways to reduce resonance by moving them out of the 2Hz to 11.67Hz range known as the dominant resonance band of earthquakes, but most of them could not achieve the performance of damping seismic response by causing resonance.

[0012] One of the countermeasures was to achieve low natural frequency so that the system's natural frequency would be 1.0 Hz or less, but there were many mechanical limitations.

[0013] This is because, in order to achieve low height retention of the system, the stiffness of the vertical spring must be designed to be very low. To do this, the diameter of the vertical spring must be increased or the number of turns of the vertical spring must be increased to lower the stiffness.

[0014] However, there was a problem in that it was difficult to meet the specifications required by the client because increasing the diameter of the vertical spring would make the width of the vertical spring too wide, and increasing the number of turns of the vertical spring would increase the height of the vertical seismic isolation system, making manufacturing difficult.

[0015] Meanwhile, as prior art to the present invention, patent application number "10-2015-0003272" titled "3D seismic isolation system with vibration-damping performance installed on an electric control panel" was filed and registered. The 3D seismic isolation system with vibration-damping performance installed on an electric control panel includes an upper frame supporting electric, electronic, and communication equipment, a lower frame fixed to the ground, and a seismic isolation system part installed between the upper frame and the lower frame and moving in a vertical direction when an earthquake occurs.

[0016] Accordingly, the purpose of the present invention is to provide a vertical seismic isolation system capable of long-period support by increasing the diameter of the vertical spring installed inside the vertical seismic isolation system to achieve a low height so that the natural frequency of the vertical seismic isolation system is 1.0 Hz or less, and by installing an inclined link rod and a horizontal spring inside the vertical seismic isolation system to provide negative stiffness (minus stiffness) characteristics in order to solve the problem of the height of the vertical seismic isolation system increasing when the number of turns is increased.

[0017] A vertical earthquake isolation system (1) having long-period support characteristics according to the present invention for achieving the above objective is a vertical earthquake isolation system (1) having long-period support characteristics that minimizes the transmission of vertical component vibrations of an earthquake to the equipment (3) to be protected from an earthquake when an earthquake occurs, wherein the system comprises: a lower frame (5) fixed to the ground; an upper frame (7) installed at a predetermined height distance from the lower frame (5) and on which the equipment (3) to be protected is mounted; and a vertical spring (9) installed between the upper frame (7) and the lower frame (5) and erected vertically at the four corners of the upper surface of the lower frame (5) to elastically support the upper frame (7). A vertical motion control means (13) is installed on each of the four sides of a space portion (11) disposed between the lower frame (5) and the upper frame (7), and is connected to the corners of the upper frame (7) and the lower frame (5) facing each other in the vertical direction, with the upper end connected to the upper frame (7) and rotated axially, and the lower end connected to the lower frame (5) and rotated axially, and is composed of a link member connected by two or more joints, so that when an earthquake occurs, the upper frame (7) and the lower frame (5) move vertically while suppressing rotational movement due to eccentricity, and equally control the vertical displacement of the upper frame (7) and the lower frame (5); A pair of horizontal springs connected to inclined link rods are installed side by side on the left and right sides of the space (11), and a means (15) for generating negative stiffness (minus stiffness) is included to generate negative stiffness (minus stiffness) when an earthquake occurs to support the upper frame (7) and to lower the vertical natural frequency of the vertical earthquake isolation system (1) having the long-period support characteristics to 1 Hz or less, thereby minimizing resonance damage caused by the earthquake.

[0018] The vertical seismic isolation system (1) having long-period support characteristics according to the present invention, configured in this way, supports the load by arranging compression springs in the horizontal direction to generate negative stiffness (minus stiffness) as a reaction force when a load is applied, thereby enabling long-period support which is difficult to achieve with a device using a conventional simple spring support mechanism.

[0019] In addition, the present invention was measured to have a vertical natural frequency of 1 Hz or less in a vibration test according to IEEE 344, which indicates that low eigenvalues ​​for the vertical natural frequency have been achieved.

[0020] In conclusion, the present invention generates negative stiffness (minus stiffness) through a mixed spring composed of horizontal and vertical springs, thereby enabling support of the load at a low device height and allowing for long-periodization in the vertical direction, thus realizing excellent seismic isolation performance.

[0021] Figure 1 is a drawing illustrating the present invention equipped with a protected facility,

[0022] Drawing 2 is a combined perspective view of the present invention,

[0023] Figure 3 is an exploded perspective view of the present invention,

[0024] Figure 4 is a drawing illustrating a vertical spring,

[0025] Figure 5 is a drawing illustrating a vertical motion control means,

[0026] Drawing 6 is a combined perspective view of the means for generating secondary rigidity,

[0027] Drawing 7 is a combined perspective view of the first sliding means,

[0028] Drawing 8 is a perspective view of a spring holder,

[0029] Figure 9 is the Minus k, Plus k graph,

[0030] Drawing 10 is a diagram of the structure with Minus k applied.

[0031] Figure 11 is a displacement-load characteristic graph,

[0032] Figure 12 is a drawing illustrating a seismic response damping means,

[0033] Figure 13 is a diagram showing the vibration versus test results according to IEEE 344.

[0034] Figure 14 is the 'floor response spectrum' of the Technical Standards for Safety of Broadcasting and Telecommunications Facilities and Communication Protocols, National Radio Research Institute Notice No. 2022-3.

[0035] *Explanation of symbols*

[0036] 1. Vertical seismic isolation system with long-period support characteristics

[0037] 3. Equipment to be Protected 5. Lower Frame

[0038] 7. Upper frame 9. Vertical spring

[0039] 11. Space section 13. Vertical motion control means

[0040] 15. Means of generating negative stiffness 17. Damper

[0041] 19. Seismic response damping means 21. Plate for fixing the upper part of a vertical spring

[0042] 23. Plate for fixing the lower part of the vertical spring

[0043] 25. Vertical spring upper fitting member 27. Vertical spring lower fitting member

[0044] 29. Intermediate link member 31. First upper connecting bracket

[0045] 33. Upper link member 35. First lower connecting bracket

[0046] 37. Lower link member 39. Horizontal spring end support member

[0047] 41. Spring holder 43. Shaft

[0048] 45. Horizontal spring 47. First sliding means

[0049] 49. 1st Inclined Link Road 51. 2nd Inclined Link Road

[0050] 53. Shaft support means 55. Horizontal spring tip support member

[0051] 57. Ball bush 59. Intermediate connecting bracket

[0052] 61. Inclined link connecting bracket 63. Horizontal spring end fitting member

[0053] 65. Horizontal spring tip fitting member 67. First displacement transmission block

[0054] 69. Second displacement transfer block 71. First upward direction conversion block

[0055] 73. 1st lower direction change block 75. 2nd upper direction change block

[0056] 77. Second lower direction change block 79. Second sliding means

[0057] 81. First connecting means 83. Second connecting means

[0058] The present invention will be described in detail below with reference to the attached drawings.

[0059] A vertical earthquake isolation system (1) having long-period support characteristics according to the present invention, as illustrated in Drawings 1 to 3, is a vertical earthquake isolation system (1) having long-period support characteristics that minimize the transmission of vertical component vibrations of an earthquake to the equipment (3) to be protected from an earthquake when an earthquake occurs, comprising: a lower frame (5) fixed to the ground; an upper frame (7) installed at a predetermined height distance from the lower frame (5) and on which the equipment (3) to be protected is mounted; and a vertical spring (9) installed between the upper frame (7) and the lower frame (5) and erected vertically at the four corners of the upper surface of the lower frame (5) to elastically support the upper frame (7). A vertical motion control means (13) configured as a link member that is installed on each of the four sides of the space portion (11) disposed between the lower frame (5) and the upper frame (7), and is connected to the corners of the upper frame (7) and the lower frame (5) facing each other in the vertical direction, with the upper end connected to the upper frame (7) and rotated axially, and the lower end connected to the lower frame (5) and rotated axially, and is connected to two or more joints, thereby enabling the upper frame (7) and the lower frame (5) to move vertically while suppressing rotational movement due to eccentricity when an earthquake occurs, and equally controlling the vertical displacement of the upper frame (7) and the lower frame (5); And a pair of horizontal springs connected to inclined link rods are installed side by side on the left and right sides of the space (11), and a means (15) for generating negative stiffness (minus stiffness) is included to generate negative stiffness (minus stiffness) when an earthquake occurs to support the upper frame (7) and to lower the vertical natural frequency of the vertical earthquake isolation system (1) having the long-period support characteristics to 1 Hz or less, thereby minimizing resonance damage caused by the earthquake by moving it out of the dominant resonance band (2 Hz~11.67 Hz) of the earthquake shown in Drawing 14.

[0060] In addition, as illustrated in Figure 3, the present invention includes a damper (17) positioned parallel to the upper stiffness generating means (15) between a pair of upper stiffness generating means (15); and an earthquake response damping means (19) installed at both ends of the damper (17), with the upper and lower ends connected to the upper frame (7) and lower frame (5), respectively, which attenuates the earthquake response characteristics of the vertical earthquake isolation system (1) having the long-period support characteristics by pushing or pulling both ends of the damper (17) according to the height gap between the upper frame (7) and lower frame (5) when an earthquake occurs.

[0061] As shown in Drawing 4, a plate-shaped upper fixing plate (21) for the vertical spring is installed on the bottom surface of the upper frame (7) facing the vertical spring (9), and a plate-shaped lower fixing plate (23) for the vertical spring is installed on the top surface of the lower frame (5) facing the vertical spring (9).

[0062] In addition, as shown in Drawing 4, a vertical spring upper fitting member (25) that is fitted into the upper center of the vertical spring (9) is installed on the bottom surface of the vertical spring upper fixing plate (21), and a vertical spring lower fitting member (27) that is fitted into the lower center of the vertical spring (9) is installed on the top surface of the vertical spring lower fixing plate (23).

[0063] As shown in Drawing 5, the vertical motion control means (13) installed on one side of the space portion (11) includes an intermediate link member (29) installed in the space between the upper frame (7) and the lower frame (5) and extending in the longitudinal direction of the corners of the upper frame (7) and the lower frame (5); an upper link member (33) installed in two or more sets at a predetermined interval in the longitudinal direction of the intermediate link member (29), with its upper end axially fixed to a first upper connecting bracket (31) fixed to the upper frame (7) and its lower end axially fixed to the intermediate link member (29); and a lower link member (37) installed in two or more sets at a predetermined interval in the longitudinal direction of the intermediate link member (29), with its upper end axially fixed to the intermediate link member (29) and its lower end axially fixed to a first lower connecting bracket (35) fixed to the lower frame (5).

[0064] A set of upper link members (33), the lower part of which is commonly connected to one of the intermediate link members (29), is arranged in pairs facing each other with the intermediate link member (29) in between, as shown in Figure 5.

[0065] Also, a set of lower link members (37), the upper part of which is commonly connected to one of the intermediate link members (29), is arranged in pairs facing each other with the intermediate link member (29) in between.

[0066] As shown in Drawing 6, the above-described means for generating strength (15) comprises: a pair of spring holders (41) installed on the lower frame (5) at a predetermined width interval and having a horizontal spring end support member (39) mounted vertically at their ends; a shaft (43) installed between the pair of spring holders (41) and fixed to the horizontal spring end support member (39) with both ends provided by the pair of spring holders (41); a horizontal spring (45) that is penetratingly coupled to the shaft (43) while lying horizontally, with a pair installed in a 1:1 ratio within each pair of spring holders (41) and with its end in contact with the horizontal spring end support member (39) provided by the spring holder (41); a first sliding means (47) installed between the two horizontal springs (45), which reciprocates in the longitudinal direction of the shaft (43) and faces the front ends of the two horizontal springs (45); and the upper part of the upper It includes a first inclined link rod (49) that is axially rotated while connected to the frame (7) and has its lower part axially fixed to one of a pair of first sliding means (47) to convert the vertical displacement of the upper frame (7) into a horizontal displacement and transmit it to one of the pair of first sliding means (47), and a second inclined link rod (51) that is axially rotated while its upper part is connected to the upper frame (7) and has its lower part axially fixed to one of the pair of first sliding means (47) that is not connected to the first inclined link rod (49) to convert the vertical displacement of the upper frame (7) into a horizontal displacement and transmit it to one of the pair of first sliding means (47) that is not connected to the first inclined link rod (49).When an earthquake occurs, if the height gap between the upper frame (7) and the lower frame (5) narrows, the angle between the first inclined link rod (49) and the second inclined link rod (51) widens, and the first inclined link rod (49) and the second inclined link rod (51) widen the gap between the pair of first sliding means (47) to contract the pair of horizontal springs (45), and the contracted pair of horizontal springs (45) elastically push the pair of first sliding means (47), so that the first inclined link rod (49) and the second inclined link rod (51), each connected to the pair of first sliding means (47), elastically support the upper frame (7).

[0067] The above horizontal spring (45) uses a compression spring.

[0068] Additionally, the above-mentioned means for generating strength (15) further includes a pair of shaft support means (53) installed between a pair of the first sliding means (47) and supporting the shaft (43).

[0069] As shown in Drawing 6, a pair of the first inclined link rods (49) are installed on both sides of the first sliding means (47) on which the first inclined link rods (49) are installed.

[0070] As shown in Drawing 6, a pair of the second inclined link rods (51) are installed on both sides of the first sliding means (47) on which the second inclined link rods (51) are installed.

[0071] As shown in Drawing 7, the first sliding means (47) comprises a horizontal spring tip support member (55) that is in contact with the tip of a horizontal spring (45) and is coupled through the shaft (43), a ball bush (57) that is coupled through the shaft (43) and slides in the longitudinal direction of the shaft (43), an intermediate connecting bracket (59) that is installed between the horizontal spring tip support member (55) and the ball bush (57) to connect the horizontal spring tip support member (55) and the ball bush (57) and is coupled through the shaft (43), and an inclined link connecting bracket (61) that is installed on the side of the ball bush (57) and to which the first inclined link rod (49) or the second inclined link rod (51) is axially fixed.

[0072] As shown in Drawing 7, a horizontal spring front fitting member (65) that fits into the center of the front end of the horizontal spring (45) is installed on one side of the horizontal spring front support member (55) facing the front end of the horizontal spring (45), and as shown in Drawing 8, a horizontal spring end fitting member (63) that fits into the center of the end end of the horizontal spring (45) is installed on one side of the horizontal spring end support member (39) facing the end end of the horizontal spring (45).

[0073] The concept of the above-mentioned strength is further explained with reference to Drawing 9 as follows.

[0074] Most materials shorten in response to compression and lengthen in response to tension.

[0075] Materials with positive stiffness (plus stiffness) require more force to resist deformation.

[0076] On the other hand, materials with high stiffness exhibit a characteristic where the force decreases with deformation.

[0077] Systems with such negative stiffness are unstable when used alone because they have the characteristic of becoming shorter during compression and longer during tension.

[0078] However, this system can be stabilized by adding a vertical spring with positive stiffness, because positive stiffness springs have the characteristic of resisting compression and repelling tension, which can compensate for the instability of negative stiffness.

[0079] In other words, the stabilization effect can be achieved by properly matching the characteristics of negative and positive stiffness.

[0080] If the above-mentioned positive stiffness is too strong, it can suppress the extreme properties of negative stiffness, and if the positive stiffness is too weak, the system may not be fully stabilized.

[0081] Therefore, by appropriately mixing the two types of springs, it is possible to improve safety while maintaining the extreme properties of negative stiffness and increase controllability, enabling their application in various fields.

[0082] The structure and principle of the secondary rigidity are explained with reference to Drawing 10 as follows.

[0083] In Figure 10, F is the vertical force and Fh is the horizontal force, is the amount of deformation in the vertical direction, is the initial length of the horizontal spring, Lh is the deformed length of the horizontal spring, Hid is the initial vertical height, a is the length of the inclined link rod connecting the moving body and the horizontal spring, b is the distance between the moving body and the wall, and β is the angle formed by the inclined link rod and any horizontal line.

[0084] In other words, by applying the principle of virtual work to the vertical force F, the following equation can be obtained.

[0085]

[0086] By the basic stiffness formula F=k*x, the following equation for a horizontal spring is obtained.

[0087] It is possible.

[0088]

[0089] tanβ can be summarized as follows.

[0090]

[0091] By the Pythagorean theorem, Lh and Hid can be expressed as follows.

[0092]

[0093] All expressions By substituting into and rearranging for the normal force, the following equation can be obtained.

[0094]

[0095]

[0096] Through the above equation, the vertical force generated according to the vertical position of the moving body can be determined when the stiffness and length of the horizontal spring, the length of the inclined link rod, and the distance between the moving body and the wall are determined.

[0097] To summarize the principle of negative stiffness, when the payload increases due to an earthquake, the angle of the inclined link rod decreases, and the compressive force of the horizontal spring increases. Therefore, from the perspective of the X direction, there is positive stiffness, +K (positive stiffness); however, from the perspective of the Y direction, since Fy = tan(β) * Fx, the repulsive force of the horizontal spring, i.e., the restoring force (vertical component), decreases, resulting in negative stiffness, -k (negative stiffness).

[0098] Referring to Figure 10, the horizontal springs connected to the inclined link rods on the left and right sides induce the system to vibrate at a specific period, thereby absorbing seismic energy and reducing the impact transmitted to the equipment.

[0099] The negative stiffness characteristic enables long-periodization. The 'negative stiffness characteristic' generated through horizontal springs allows for vertical motion with a longer period than conventional vertical seismic isolation systems.

[0100] This effectively absorbs earthquake energy and minimizes the impact transmitted to the equipment.

[0101] Vertical springs provide additional support and play a role in increasing the stability of the system.

[0102] The vertical motion control means effectively restricts horizontal and rotational motion, allowing only stable vertical motion.

[0103] The performance of a vertical seismic isolation system with negative stiffness characteristics is described as follows.

[0104] As the first restoring force characteristic, the displacement-load characteristic graph shown in Figure 11 shows the restoring force of the system returning to its original position when subjected to an external shock.

[0105] This ensures that the protected equipment remains stable even after a sudden shock, such as an earthquake.

[0106] The second characteristic is having a low natural frequency; the low eigenvalue of 1 Hz or less implemented in this system means that the vibration period of the system itself is long. In other words, it reacts slowly to external shocks, mitigating the shock transmitted to the equipment.

[0107] The results of the seismic wave excitation experiment, which simulated actual seismic waves, showed that it effectively absorbs seismic shocks in various earthquake situations to protect onboard equipment.

[0108] Meanwhile, as shown in Drawing 12, the seismic response damping means (19) comprises: a first displacement transmission block (67) installed within the space (11), extending in the horizontal direction of the lower frame (5), with the leading end of the damper (17) axially fixed in the center; a second displacement transmission block (69) installed within the space (11), extending in the horizontal direction of the lower frame (5), with the trailing end of the damper (17) axially fixed in the center; a pair of first upper direction conversion blocks (71) installed on the bottom surface of the upper frame (7) facing both ends of the first displacement transmission block (67), with a slope surface formed on one side facing the first displacement transmission block (67); and a slope surface formed on one side facing the first displacement transmission block (67), along the upper frame (7). A pair of first lower direction change blocks (73) installed at a position that does not collide with a pair of descending first upper direction change blocks (71); a pair of second upper direction change blocks (75) installed on the bottom surface of an upper frame (7) facing both ends of the second displacement transfer block (69) and having a slope surface formed on one side facing the second displacement transfer block (69); a pair of second lower direction change blocks (77) installed on the top surface of a lower frame (5) facing both ends of the second displacement transfer block (69) and having a slope surface formed on one side facing the second displacement transfer block (69), installed at a position that does not collide with a pair of second upper direction change blocks (75) descending along the upper frame (7); the first upper direction change block (71), the first lower direction change block (73), the second upper direction change block (75), and the second lower direction change A second sliding means (79) installed on the slope surface of the block (77),A first connecting means (81) that moves in the longitudinal direction of the slope surface provided in the first upper direction conversion block (71) and the first lower direction conversion block (73) by means of the second sliding means (79) respectively installed in the first upper direction conversion block (71) and the first lower direction conversion block (73) and the end of the first displacement transmission block (67) and the first upper direction conversion block (71) and the first lower direction conversion block (73) respectively, and a second sliding means (79) respectively installed in the second upper direction conversion block (75) and the second lower direction conversion block (77) and the end of the second displacement transmission block (69) and the end of the second displacement transmission block (69) and the second upper direction conversion block (75) and the second lower direction conversion block (77) and the second upper direction conversion block (75) and the second lower direction conversion block (77) respectively installed in the upper direction conversion block (75) and the second lower direction conversion A second connecting means (83) that moves along the longitudinal direction of the slope surface provided in the second upper direction changing block (75) and the second lower direction changing block (77) by means of a second sliding means (79) installed in each block (77) is included, such that when the height gap between the upper frame (7) and the lower frame (5) narrows, the gap between the first displacement transmission block (67) and the second displacement transmission block (69) narrows, thereby narrowing the length of the damper (17), and when the height gap between the upper frame (7) and the lower frame (5) widens, the gap between the first displacement transmission block (67) and the second displacement transmission block (69) widens, thereby widening the length of the damper (17), and the damper (17), whose length is adjusted according to the height gap between the upper frame (7) and the lower frame (5), dampens the seismic response characteristics.

[0109] The second sliding means (79) above uses an LM guide rail and an LM guide block that reciprocates along the LM guide rail.

[0110] The vertical seismic isolation system (1) having long-period support characteristics according to the present invention, configured in this way, supports the load by arranging compression springs in the horizontal direction to generate negative stiffness as a reaction force when a load is applied, thereby enabling long-period support which is difficult to achieve with a device using a conventional simple spring support mechanism.

[0111] In addition, as shown in Figure 13, the vertical natural frequency was measured to be 0.75 Hz in the vibration test according to IEEE 344, which indicates that low eigenvalues ​​for the vertical natural frequency have been achieved.

[0112] In conclusion, the present invention can generate a load-bearing capacity at a low device height by using a mixed spring composed of a horizontal spring (45) and a vertical spring (9), and can achieve excellent seismic isolation performance by enabling long-term vertical movement.

Claims

1. A vertical earthquake isolation system (1) having long-period support characteristics that minimize the transmission of vertical component vibrations of an earthquake to the equipment (3) to be protected from an earthquake, and is equipped with equipment (3) to be protected from an earthquake, wherein A lower frame (5) fixed to the ground; An upper frame (7) installed at a predetermined height distance from the lower frame (5) and on which the equipment to be protected (3) is mounted; A vertical spring (9) installed between the upper frame (7) and the lower frame (5) and erected vertically at the four corners of the upper surface of the lower frame (5) to elastically support the upper frame (7); A vertical motion control means (13) is installed on each of the four sides of a space portion (11) disposed between the lower frame (5) and the upper frame (7), and is connected to the corners of the upper frame (7) and the lower frame (5) facing each other in the vertical direction, with the upper end connected to the upper frame (7) and rotated axially, and the lower end connected to the lower frame (5) and rotated axially, and is composed of a link member connected by two or more joints, so that when an earthquake occurs, the upper frame (7) and the lower frame (5) move vertically while suppressing rotational movement due to eccentricity, and equally control the vertical displacement of the upper frame (7) and the lower frame (5); and includes a pair of negative stiffness generating means (15) installed side by side on the left and right sides of the space (11), which generate negative stiffness (minus stiffness) when an earthquake occurs to support the upper frame (7) and lower the vertical natural frequency of the vertical earthquake isolation system (1) having the long-period support characteristics to 1 Hz or less to minimize resonance damage caused by the earthquake. The above-mentioned means for generating strength (15) comprises a pair of spring holders (41) installed on the lower frame (5) at a predetermined width interval and equipped with a horizontal spring end support member (39) that is vertically positioned at the end, and A shaft (43) installed between a pair of the above spring holders (41) and fixed to a horizontal spring end support member (39) having both ends provided in a pair of the above spring holders (41), A horizontal spring (45) that is connected through the shaft (43) while lying horizontally, and a pair of which are installed one-to-one within a pair of spring holders (41), with the end of which is in contact with a horizontal spring end support member (39) provided in the spring holder (41). A pair of first sliding means (47) installed between the two horizontal springs (45), reciprocating along the length of the shaft (43), and each facing the front end of the two horizontal springs (45), A first inclined link rod (49) in which the upper part is connected to the upper frame (7) and rotates axially, and the lower part is axially fixed to one of a pair of first sliding means (47) to convert the vertical displacement of the upper frame (7) into a horizontal displacement and transmit it to one of a pair of first sliding means (47). and a second inclined link rod (51) which is axially rotated with its upper end connected to the upper frame (7) and its lower end is axially fixed to one of the pair of first sliding means (47) that is not connected to the first inclined link rod (49), converting the vertical displacement of the upper frame (7) into a horizontal displacement and transmitting it to one of the pair of first sliding means (47) that is not connected to the first inclined link rod (49). A vertical earthquake isolation system (1) having long-period support characteristics, characterized in that when an earthquake occurs, the height gap between the upper frame (7) and the lower frame (5) narrows, causing the angle between the first inclined link rod (49) and the second inclined link rod (51) to widen, and the first inclined link rod (49) and the second inclined link rod (51) widen the gap between a pair of first sliding means (47) to contract a pair of horizontal springs (45), and the contracted pair of horizontal springs (45) elastically push the pair of first sliding means (47) so that the first inclined link rod (49) and the second inclined link rod (51), each connected to a pair of first sliding means (47), elastically support the upper frame (7).

2. In Paragraph 1, A damper (17) lying parallel to the stiffness generating means (15) between a pair of the above-mentioned stiffness generating means (15); A vertical earthquake isolation system (1) having long-period support characteristics, characterized by including an earthquake response damping means (19) installed at both ends of the damper (17), with the upper and lower ends connected to the upper frame (7) and lower frame (5), respectively, and which attenuates the earthquake response characteristics of the vertical earthquake isolation system (1) having long-period support characteristics by pushing or pulling both ends of the damper (17) according to the height gap between the upper frame (7) and lower frame (5) when an earthquake occurs.

3. In Paragraph 2, The above earthquake response damping means (19) comprises a first displacement transmission block (67) installed within the space (11) and extending in the horizontal direction of the lower frame (5), with the tip of the damper (17) axially fixed in the center, and A second displacement transfer block (69) installed within the above space (11), extending in the horizontal direction of the lower frame (5), with the end of the damper (17) axially fixed in the center, A pair of first upper direction conversion blocks (71) installed on the bottom surface of an upper frame (7) facing both ends of the first displacement transfer block (67), and having a slope surface formed on one surface facing the first displacement transfer block (67), A pair of first lower direction conversion blocks (73) installed on the upper surface of a lower frame (5) facing both ends of the first displacement transmission block (67), a slope surface formed on one surface facing the first displacement transmission block (67), and installed at a position that does not collide with a pair of first upper direction conversion blocks (71) descending along the upper frame (7). A pair of second upper direction conversion blocks (75) installed on the bottom surface of the upper frame (7) facing both ends of the second displacement transfer block (69) and having a slope surface formed on one surface facing the second displacement transfer block (69), A pair of second lower direction conversion blocks (77) installed on the upper surface of a lower frame (5) facing both ends of the second displacement transmission block (69), a slope surface formed on one surface facing the second displacement transmission block (69), and installed at a position that does not collide with a pair of second upper direction conversion blocks (75) descending along the upper frame (7). A second sliding means (79) installed on the slope surface of the first upper direction changing block (71), the first lower direction changing block (73), the second upper direction changing block (75), and the second lower direction changing block (77), A first connecting means (81) that connects the end of the first displacement transmission block (67) and the second sliding means (79) respectively installed in the first upper direction conversion block (71) and the first lower direction conversion block (73) facing the end of the first displacement transmission block (67) in the vertical direction, and moves in the longitudinal direction of the slope surface provided in the first upper direction conversion block (71) and the first lower direction conversion block (73) by the second sliding means (79) respectively installed in the first upper direction conversion block (71) and the first lower direction conversion block (73); and a second sliding means (79) installed respectively in a second upper direction conversion block (75) and a second lower direction conversion block (77) facing the end of the second displacement transmission block (69) in the vertical direction, and a second connecting means (83) that moves in the longitudinal direction of the slope surface provided in the second upper direction conversion block (75) and the second lower direction conversion block (77) by means of the second sliding means (79) installed respectively in the second upper direction conversion block (75) and the second lower direction conversion block (77). When the height gap between the upper frame (7) and the lower frame (5) is narrowed, the gap between the first displacement transmission block (67) and the second displacement transmission block (69) is narrowed, thereby shortening the length of the damper (17). As the height gap between the upper frame (7) and the lower frame (5) widens, the gap between the first displacement transmission block (67) and the second displacement transmission block (69) widens, and the length of the damper (17) is widened. A vertical seismic isolation system (1) having long-period support characteristics, wherein the damper (17), whose length is adjusted according to the height gap between the upper frame (7) and the lower frame (5), dampens seismic response characteristics.

4. In Paragraph 1, The vertical motion control means (13) installed on one side of the above space (11) is installed in the space between the upper frame (7) and the lower frame (5) and includes an intermediate link member (29) that extends in the longitudinal direction of the corners of the upper frame (7) and the lower frame (5); Two or more sets are installed at predetermined intervals along the longitudinal direction of the intermediate link member (29), and an upper link member (33) is axially fixed to a first upper connecting bracket (31) whose upper end is fixed to the upper frame (7) and whose lower end is axially fixed to the intermediate link member (29); A vertical seismic isolation system (1) having long-period support characteristics, characterized by including at least two sets installed at a predetermined interval in the longitudinal direction of the intermediate link member (29), and a lower link member (37) whose upper part is axially fixed to the intermediate link member (29) and whose lower part is axially fixed to a first lower connecting bracket (35) which is fixed to the lower frame (5).

5. In Paragraph 1, The first sliding means (47) above is in contact with the front end of the horizontal spring (45) and has a horizontal spring front end support member (55) that is coupled through the shaft (43), and A ball bush (57) that is coupled through the shaft (43) and slides along the length of the shaft (43), An intermediate connecting bracket (59) installed between the horizontal spring tip support member (55) and the ball bush (57), connecting the horizontal spring tip support member (55) and the ball bush (57) and penetratingly coupled to the shaft (43), A vertical seismic isolation system (1) having long-period support characteristics, characterized by including an inclined link connecting bracket (61) installed on the side of the ball bush (57) and to which the first inclined link rod (49) or the second inclined link rod (51) is axially fixed.

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