JP2006342884A - Base isolation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spring type base isolation device capable of solving at least one of the problems existent in the "spring type base isolation device" having a spring arranged horizontally (size of a base isolation base is large, spring set force is large, spring characteristics have peculiarities, reduction of natural frequency of the base isolation device is difficult, and installation of a damper is difficult). <P>SOLUTION: (1) This base isolation device 10 has the spring 14 and a spring shaft axis having an angle of 35 degrees or more and 90 degrees or less for the horizontal direction of the spring 14. (2) This base isolation device has a spring shaft axis having an angle of 90 degrees for the horizontal direction of the spring 14. (3) This base isolation device has a spring shaft axis having an angle of 35 degrees or more and less than 90 degrees from the horizontal direction of the spring 14. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a seismic isolation device, and more particularly to a spring-type seismic isolation device whose return force is a spring force.

Various seismic isolation devices have been developed and used in order to protect earthquake-resistant valuables such as historical relics, arts and crafts, and precision machinery from damage caused by earthquakes.
Seismic isolation devices are divided into “gravity type” and “spring type” depending on the method of generating the return force. A representative example is shown in FIGS.

Each will be briefly described.
(B) Gravity type (Fig. 26: Ball type, Fig. 27: Linear bearing type)
A device in which the base isolation table 101 is supported by a curved plate 102 and a ball 103, and when it moves left and right, the base isolation table 101 is slightly lifted and returned to its original position by gravity. Basically, it moves on the principle of “pendulum” and has a characteristic that “natural frequency” is determined regardless of the mass of the base isolation table 101 and the object. If the natural frequency is made sufficiently low, vibrations at frequencies higher than that can be cut off, and the roll of the earthquake can be mitigated.

(B) Laminated rubber type (Fig. 28)
A device that uses laminated rubber 104, an anisotropic rubber, soft on the left and right and hard on the top and bottom to escape the roll of an earthquake. The laminated rubber 104 serves as a bearing that absorbs left and right shaking, and at the same time uses the elasticity of the rubber as a restoring force. In addition, the damping effect inherent in rubber absorbs the vibration of seismic waves and converts it into heat, reducing the vibration energy. Reference numeral 105 denotes a base isolation table, and 106 denotes a base.
(C) Spring type (Fig. 29)
The spring-type seismic isolation device consists of two components.
Ball 107: A plurality (three or more) of balls 107 are inserted between the base 108 and the base isolation table 109, and serve as a bearing that absorbs horizontal shaking of the base isolation table 109 with respect to the base 108. Since the ball receiving surface 110 is a flat surface, the base isolation table 109 is not lifted and there is no action of gravity. The ball 107 supports the vertical load of the base isolation table 109.
Spring 111: has a role of returning the horizontal shift between the base 108 and the base isolation table 109. In addition, a spring-mass mechanism having the seismic isolation table 109 as a mass is configured. Its natural frequency f is
f = {1 / (2π)} (K / M) ^1/2
K: Spring constant
M: Mass (base-isolated table + object)
However, the seismic isolation effect can be demonstrated by making f small enough. Further, in order to absorb more vibration energy, a hydraulic damper, a viscous damper, or the like can be used in combination.

Examples of spring-type seismic isolation devices that can be generally considered are shown in FIGS.
Since the seismic isolation device is desired to have a quadrangular shape that fits when installed, the spring type is composed of four balls 107 and four horizontally arranged springs 111 as shown in FIGS. Efficient.
Since the spring 111 swings as the base 109 moves when the base isolation table 109 operates, the swing range A is checked by the method shown in FIG. 32 so as not to interfere with the ball and the ball cradle. In addition, it is arranged with the necessary distance.
Japanese Unexamined Patent Publication No. 09-191985

The conventional spring-type seismic isolation device has the following problems.
(I) The base isolation table size is large.
(Ii) Large spring setting force.
(Iii) There is a flaw in the spring characteristics. (Direction, generation of orthogonal components, etc.)
(Iv) It is difficult to reduce the natural frequency of the seismic isolation device. ...... Seismic isolation performance is limited.
(V) It is difficult to install a damper.
I will describe each problem in more detail.

(I) The base isolation table size is large.
As can be seen from FIGS. 30 to 32, the size of the base is determined by the length of the spring.
The spring set length is the spring design length (initial length) plus the minimum elongation and half of the operating length.
In FIG. 33, Lo = 0.2 (the length required from the spring use condition)
Ln = 0.02
Lw = 0.4
Ls = Lo + Ln + Lw / 2 = 0.2 + 0.02 + 0.4 / 2 = 0.42
Since a pair of springs are arranged in parallel with the sides, the size of the base is a square with one side of 0.84 m or more.
The length of one side is more than double the size of the gravity type seismic isolation device, which is more than twice the diameter of the pan (0.4m).

(Ii) Large spring setting force.
As can be seen from the explanation of (i), the length of the spring when set is Ls = 0.42 m, and the 0.2 m spring is extended to a length of 0.42 m and set. The extension amount of the spring at the time of setting corresponds to almost half of the maximum extension amount of the spring, and a large stress is always applied when the spring is used.
Since this state is maintained for a long time from the use conditions of the seismic isolation device, there is a concern about the deterioration of the spring.

(Iii) There is a flaw in the spring characteristics.
FIG. 34 shows the spring strength when the seismic isolation device is pulled in various directions.
The horizontal axis is the tension direction, and the angle of 0 degrees indicates the spring direction. Therefore, at an angle of 90 degrees, it becomes the direction of the adjacent spring. The calculation conditions were Ls = 0.42m, Lw = 0.4m, K = 100N / m, and four lengths of 0.05, 0.10, 0.15 and 0.20m were examined.
As can be seen from FIG. 34, when the pulling amount is large, the spring force in the direction without the spring is small.
In addition, in the direction other than the spring direction 0, 45, 90 degrees, the force of the orthogonal component is generated.
There is a concern that this spring force wrinkle (difference depending on direction and orthogonal component) may cause extra motion (difference in deflection due to direction, occurrence of rotation, etc.) in the base isolation table.
FIG. 35 shows the spring characteristics when the base isolation table is pulled in the direction in which the spring is attached (0 degree) and in the direction without the spring (45 degree).
The line b (center) in FIG. 35 is the spring strength when two springs with K = 100 N / m are arranged in parallel. The spring in the 0 degree direction becomes slightly stronger than the linear spring as the displacement increases, and the spring in the 45 degree direction becomes slightly weaker. However, roughly speaking, it can be considered that the spring characteristics are almost proportional to the displacement (linear) in all directions.
In the following simulation, for simplicity, it is treated as a linear spring in all directions.

(Iv) It is difficult to reduce the natural frequency of seismic isolation devices.
FIG. 36 is a conceptual diagram of a spring horizontal arrangement type seismic isolation device. Since the natural frequency is a spring-mass model, it can be easily obtained by the above formula. Since the model has a spring on both sides, the spring force is doubled and the natural frequency f is
f = {1 / (2π)} (K / M) ^1/2
It becomes.

For example, when calculating for the study example, K = 100 N / m, M = 500 kg, f = 0.1007 Hz.
In order to cope with various earthquakes, it is desirable to set f <0.06Hz (the lower limit frequency of seismic waves), but this device has a higher natural frequency, so it does not satisfy the requirements for seismic isolation devices. To reduce the natural frequency by half in order to achieve the target, it is necessary to increase M by a factor of 4 or to reduce K by a factor of four. 4 times the mass increase is too large, and if the spring constant is set to a quarter of 25N / m, there is a concern that the horizontal spring with a set length of 0.42m may cause slackness due to vibration or its own weight. Is not realistic. In other words, with the spring horizontal arrangement, it is difficult to reduce the natural frequency to the target.

In this seismic isolation model, the actual seismic data Kobe earthquake NS wave ……… Intense, short period, short time earthquake
El centro earthquake EW wave ......... Slow, long period and long time earthquakes are put in and the behavior of this base is simulated as follows.
37 and 38 show acceleration. Line a shows the acceleration waveform of the earthquake, and line b shows the acceleration waveform of the base isolation table.
It can be seen that the acceleration was suppressed to almost zero in the Kobe earthquake, but considerable acceleration remained in the El centro earthquake.
Next, the calculation results of the amplitude are shown in FIGS. Line c shows the relative movement amount of the base isolation table and the ground.
Comparing the two figures, the Kobe earthquake can exhibit the seismic isolation function, but the El centro earthquake expanded the amplitude, and the relative movement between the platform and the ground exceeded the spring operating width of ± 0.2 m. It turns out that the function of the device cannot be demonstrated.
In summary, there is a limit to the seismic isolation performance when trying to make the spring horizontal seismic isolation device of this size.

(V) It is difficult to install a damper.
Since the base isolation table efficiently absorbs vibrations having a high frequency (seismic wave component exceeding the natural frequency), the attenuation of acceleration is relatively easy, but the speed and amplitude may be increased. In such a case, it is effective to install a “damper” that can suppress the “speed”.
The following three types of dampers can be considered, and each has the following characteristics.

I. Fluid damper 112 (FIG. 41)
〔principle〕
A method of using resistance of a flow when a fluid passes through a narrow passage (slit) 113. If the passage is narrow, laminar flow resistance occurs, and resistance proportional to the 0.9 to 1.0th power is generated in the reverse direction of the speed. That is,
D = -CV 0.9-1 ^xsign (V)
However, sign (V) is a sign function defined as follows.
When V> 0, sign (V) = 1
When V = 0, sign (V) = 0
When V <0, sign (V) =-1
〔advantage〕
Since the resistance is almost proportional to the speed, it is most effective for speed control. (High performance)
〔problem〕
Usually, it is installed along the spring, but the set length is about 5 times the stroke (s) due to its structure (see FIG. 41), which is much longer than about twice that of the spring.
Therefore, if the stroke is s = 0.2m, a set length of 1.0m is required, which leads to an increase in the size of the seismic isolation device.

B. Viscous damper 114 ((a), (b) in FIG. 42, (a), (b), (c), (d), (e) in FIG. 43)
〔principle〕
A method that uses the “drag” (boundary layer resistance) of a viscous fluid sandwiched between two surfaces. In the reverse direction of the speed, a resistance proportional to the 0.5 to 0.8th power is generated.
That is,
D = -CV ^0.5-0.8 xsign (V)
〔advantage〕
It is possible to perform damping in all directions with one, and there is no need to install it in every required direction like a fluid damper. In addition, the set size is about 3.5 times the stroke s, and it is shorter than the fluid damper, making it easy to install in a seismic isolation device. ((A), (b), (c), (d), (e) in FIG. 43)
〔problem〕
Since it is a disk shape, it must be arranged at the center of the apparatus, and the spring 115 and the ball 116 cannot be arranged at that position, so that the size is increased. An example is shown in (a), (b), and (c) of FIG.
43 shows the case with a damper ((A), (B), (C) in FIG. 43) and the case without a damper ((D), (E) in FIG. 43) at the same scale. In the case of being present, the plane area of the seismic isolation device will be increased by approximately 2.9 times (1.7 times in length) compared to the case without a damper.

C. Friction damper 117 (Fig. 44: Solid friction type, Fig. 45: Rolling type)
〔principle〕
A sliding surface is formed between the base isolation table 118 and the ground 119 to generate resistance by frictional force (FIG. 44). There is also a method of increasing the rolling resistance by changing the contact surface 121 of the ball 120 (FIG. 45). The force by this method depends on the direction of speed (acts in the opposite direction of speed), but not on the magnitude of the speed. However, it is proportional to the contact surface pressure (M).
That is,
〔advantage〕
Simple structure and low cost. There is no increase in space for installation.
〔problem〕
Since the damping force is not proportional to the speed, a sudden change in resistance force occurs when the speed is reversed, and stick-slip (slip is restrained or slipped) occurs. Therefore, the operation of the base isolation table 118 becomes unstable, which is not preferable as a damper.

  An object of the present invention is to provide a spring-type seismic isolation device that solves at least one of the above-mentioned problems (i) to (v), which exists in a “spring-type seismic isolation device” in which springs are arranged horizontally. There is.

The present invention for achieving the above object is as follows.
(1) A fixed base, a base-isolated base that can move in a horizontal direction with respect to the fixed base, a ball arranged between the fixed base and the base-isolated base, one end being a fixed base and the other being a base-isolated base A seismic isolation device having a spring for returning the base isolation table to the origin position, wherein the spring has a spring axis having an angle of not less than 35 degrees and not more than 90 degrees with respect to the horizontal direction. Seismic device.
(2) The seismic isolation device according to (1), wherein the spring has a spring axis having an angle of 90 degrees with respect to a horizontal direction.
(3) The seismic isolation device according to (1), wherein the spring has a spring axis having an angle of 35 degrees or more and less than 90 degrees from the horizontal direction.
(4) The seismic isolation device according to (1), further comprising a damper.

  According to the seismic isolation device of any one of the above (1) to (4), the spring has a spring axis having an angle of 35 degrees or more and 90 degrees or less with respect to the horizontal direction, and will be described in detail below. As described above, the problems (i) to (v) are solved or reduced.

The seismic isolation device 10 of the present invention will be described with reference to FIGS.
The seismic isolation device 10 of the present invention includes a fixed base 11, a base isolation table 12 movable in a horizontal direction with respect to the fixed base 11, a ball 13 disposed between the fixed base 11 and the base isolation table 12, And a spring 14 for returning the base isolation table 12 to the origin position, one end of which is connected to the fixed base 11 and the other end connected to the base isolation base 12. The spring 14 has a spring axis 15 having an angle of 35 degrees or more and 90 degrees or less with respect to the horizontal direction.
The spring 14 may have a series arrangement having a spring axis 15 having an angle of 90 degrees with respect to the horizontal direction.
Alternatively, the spring 14 may be disposed obliquely with the spring axis 15 having an angle of 35 degrees or more and less than 90 degrees from the horizontal direction.
The seismic isolation device 10 may further include a damper 16.
Hereinafter, the configuration of the present invention will be described in more detail together with the reason why the above problems (i) to (v) are solved or alleviated by adopting the configuration (the reason is also the operation and effect of the present invention). Explained.

(A) Upright arrangement of the spring By arranging the spring 14 of the base isolation table 12 upright as shown in FIGS. 1 and 2 (so that the spring axis 15 has an angle of 90 degrees with respect to the horizontal direction). Problems (i), (ii), (iii), (iv), and (v) are all solved. The reasons for solving each problem are described below.

In the case of the upright arrangement, in order to avoid interference between the tray portion 17 and the spring 14, it is better to lower the tray 17 (t is small). Accordingly, it is necessary to increase the diameter D of the ball 13 correspondingly, and in the examples of FIGS. 1 and 2, the ball diameter D is double that of the examples studied so far.
Examination of interference with the spring 13 is carried out by drawing as shown in FIGS. In the present examination example, the center of the plate C and the spring center need to be separated from each other by 28 mm or more, and as shown in FIG. 1, consideration is given so as not to arrange the spring center 15 within φ28 mm from the plate center C.

Problem (i): Eliminating the size When the plan diagrams of the horizontal arrangement (conventional) and the upright arrangement (the upright arrangement of the present invention and the upright arrangement of the diagonal arrangement) are shown at the same scale, FIG. It becomes like (d). All of them are arranged with a space so that there is no mutual interference when moving in the event of an earthquake stroke of ± 200mm. By making it upright, it is possible to reduce the size by 35% in plane area (20% in length), and the problem of large size is improved. The height is slightly higher to prevent interference.

Problem (ii): Eliminating the large spring set force In the method of placing the spring parallel to the direction of movement of the base isolation table (horizontal plane) ((c) in FIG. 6), the spring set length Ls is the center of the spring operating range Lw. . Therefore, the set force is extended by Ln + Lw / 2, and the set force becomes a considerably large value.
The upright arrangement spring of the present invention ((A) in FIG. 6) extends only Ln at the time of setting, the setting load is very small, and the spring is not forced at normal times. When the spring is actuated, as shown in FIG. 6B, the amount of extension is determined by the amount of movement regardless of the direction, so the spring diagram is as shown in FIG.
In the upright arrangement spring of the present invention, the spring elongation at the time of setting may be the minimum elongation Ln required for setting from the above relationship, and the setting load can be kept low.

Problem (iii): Elimination of wrinkles of spring characteristics As shown in FIG. 7, when the upper end spring 14 is pulled in the horizontal plane direction, the same tension can be obtained regardless of which direction it is pulled. That is, there is no wrinkle due to the pulling direction. Further, there is no component force perpendicular to the pulling direction.
Therefore, as the number of springs is increased, a spring force simply added can be obtained. The spring force is Fs = K {(Ls ² + z ² ) ^1/2 −Ls}
F = Fs × z / (Ls ² + z ² ) ^1/2
It is.

Problem (iv): Elimination of difficulty in lowering the natural frequency The spring characteristics of the upright spring 14 are nonlinear as shown in FIG. In this way, the natural frequency of the base can be lowered by using a spring that is weak at the initial stage of pulling and becomes stronger as it is pulled.
Figure 8 shows Lo = 0.1m
Ln = 0.02m
Ls = Lo + Ln = 0.12m
K = 100N / m
The spring characteristic at the time of is shown.
Let us estimate the effect of such a nonlinear spring.
Series-arranged springs work equally in all directions, so half the number of horizontal-arranged springs is sufficient. Therefore, two upright springs correspond to four horizontally arranged.
The characteristics of both springs are shown in the same diagram as shown in FIG. When calculating the resonance point when using each spring,
Horizontal arrangement; f = 1.007Hz
Upright arrangement; f = 0.064Hz
Thus, the case of the upright arrangement is considerably lower.
Note that the resonance point of the upright arrangement is calculated by freely vibrating the simulation model. (Fig. 10)
FIG. 11 shows the behavior of the base isolation table when the ElcentroEW seismic wave acts on the upright spring isolation device. This is a significant improvement over the horizontal arrangement (FIGS. 43 and 44), and the effect can be confirmed. However, this has not yet reached a sufficient level, and further improvements such as lowering the spring constant are necessary.
As described above, since the spring characteristics are non-linear with an upright spring, the natural frequency of the seismic isolation device can be reduced and the seismic isolation performance can be improved.

Problem (v): Improving the difficulty of damper placement With an upright placement spring, the number of springs can be halved (two), so the placement is slightly improved as shown in Figs. (15% reduction in area). However, because the damper 16 itself is large, the problem is not solved but only reduced.

(B) Diagonal arrangement of spring The diagonal arrangement of the spring refers to a case where the neutral spring 14 is set slightly inclined rather than upright. In that case, the spring 14 has a spring axis 15 having an angle of 35 degrees or more and less than 90 degrees from the horizontal direction. In FIG. 13, (A), (B), and (C) indicate an upright arrangement, and (D) and (E, (F) indicate an oblique arrangement.
The diagonal arrangement shortens the distance between the spring 14 and the tray 17 and further reduces the size of the apparatus (FIG. 13).
14 (a), (b), (c), and (d) of FIG. 14 show an example in which the size of both springs is reduced as much as possible by taking into account the difference in contour (outer shape) and using two springs that cannot be arranged horizontally. It was. 14A and 14B show the case where the upright arrangement is provided, and (C) and (D) are the oblique arrangement.
As a result, the upright 78 × 90 becomes diagonal 72 × 86, and the area can be reduced by 12%. Since the area ratio of the contour itself is reduced by 27%, the efficiency is slightly worse.
However, the oblique arrangement has some side effects and will be described below.

Side effect 1: Spring characteristics 癖 The spring characteristics of an obliquely arranged spring can be calculated by the following method.
Consider a spring as shown in FIG. 15 in which a spring having a length Ls when set is arranged at a height H and an offset s.
With this model, the spring force Ft in the pulling direction when the upper end Q of the spring is pulled in the direction of the angle θ is calculated.
From geometric relationships,
H = (Ls ² −s ² ) ^1/2
From FIG.
xs ＝ x × sin θ
xc ＝ x × cos θ
L ′ = {(s + xc) ² + xs ² } ^1/2
From FIG.
L = (H ² + L ′ ² ) ^1/2
Spring direction reaction force F is
F = K × (L−L ₀ ) The horizontal component is
F ′ = F × L ′ / L
The shift angle ψ in the reaction force direction is
φ = arccos (xs / L ′)
ξ = arccos (xs / x)
ψ = abs (φ−ξ)
The reaction force Ft in the pull direction is
Ft = F ′ × cosψ
Actually, two springs are arranged facing each other as shown in FIG. 18, so that it is necessary to add the two spring forces.

The spring specifications on the opposite side are as shown in FIG.
From geometric relationships,
H = (Ls ² −s ² ) ^1/2
From FIG.
xs ＝ x × sin θ
xc ＝ x × cos θ
L ′ = {(− s + xc) ² + xs ² } ^1/2
From FIG.
L = (H ² + L ′ ² ) ^1/2
Spring direction reaction force F is
F = K × (L−L ₀ ) The horizontal component is
F ′ = F × L ′ / L
The shift angle ψ in the reaction force direction is
φ = arccos (xs / L ′)
ξ = arccos (xs / x)
ψ = abs (φ−ξ)
Pull direction reaction force Ft is
Ft = F ′ × cosψ
And the same idea as in the previous case.

If this spring force is Ft ', the total spring force Fta is
Fta = Ft + Ft '
And it can be calculated.

Here, the actual spring force is calculated under the following conditions.
Dimensional specifications: s = 0.1m, Lo = 0.1m, Ls = 0.12m, K = 100N / m,
Pull length; x = 0.01, 0.02, 0.03, 0.04, ………, 0.20 m
Pull angle: θ = 0, 10, 20, 30, ………, 180 degrees

FIG. 22 shows the change in spring force with respect to the pulling direction (θ).
This spring has a hook with different spring strengths depending on the pulling direction (θ) and the stroke (x), and there is a concern that the direction of the seismic isolation performance may be improved.

  FIG. 23 shows the spring characteristics themselves with the spring force with respect to the pulling stroke. The spring characteristics when pulled in the 90 degree direction are almost the same as the upright spring (line a), and the spring is weaker in the other directions. Both are suitable for seismic isolation devices because of their downward convex characteristics.

FIG. 25 shows the result when the offset amount of the oblique arrangement in FIG. 24 is changed from s = 0.1 m to s = 0.03 m.
As shown in FIG. 25, the spring characteristics are almost the same as those in the case of standing up regardless of the pulling direction, and there is no concern about “spring characteristic wrinkles”. In the case of an oblique arrangement, it is important to suppress the spring set angle.
S = 0.1: Spring set angle = 34 degrees
s = 0.03: Spring set angle = 76 degrees

Side effect 2: By arranging the spring setting force diagonally, the spring stretches during setting. (Right table in FIG. 25)
Therefore, there is a problem that the spring setting force is large, but it is much smaller than that in the horizontal arrangement.

Side effects summary:
Although there are some side effects (the above-mentioned side effect 1 and side effect 2), if there is a need for suppression of the overall dimensions, prevention of interference, etc., oblique arrangement should be carried out. However, it is desirable that the spring set angle (angle of the spring axis with respect to the horizontal direction) be 35 degrees or more.

It is a top view in case the spring is an upright spring of the seismic isolation device of the present invention. It is sectional drawing (AA sectional drawing of FIG. 1) of the seismic isolation apparatus of this invention. It is sectional drawing before the base isolation table movement used for examination of interference with the plate and spring of the base isolation apparatus of FIG. It is sectional drawing after the base isolation table movement used for examination of interference with the plate and spring of the base isolation device of FIG. It is a figure which shows that the size of the seismic isolation device of an upright spring of the present invention is smaller than that of a conventional horizontal spring seismic isolation device, and (A) is a plan view in the case of the spring upright arrangement of the present invention, (B) FIG. 4 is a cross-sectional view taken along line AA of the apparatus (a), (c) is a plan view when a conventional spring is horizontally disposed, and (d) is a cross-sectional view taken along line AA of the apparatus (c). FIG. 6 is a diagram showing that the spring setting force of the vertical spring seismic isolation device of the present invention is smaller than that of a conventional horizontal spring seismic isolation device, wherein (a) is the load / spring length in the case of the spring upright arrangement of the present invention. (B) is a cross-sectional view of the spring portion of the seismic isolation device in the case of the spring upright arrangement of the present invention, and (c) is a graph of load / spring length in the case of a conventional spring horizontal arrangement. FIG. 5 is a cross-sectional view of a spring and its vicinity showing that the upright spring seismic isolation device of the present invention eliminates the problem of spring characteristics as compared with a conventional horizontal spring seismic isolation device. It is a spring characteristic figure (load / displacement graph) of the seismic isolation device of an upright spring of the present invention. It is a comparison of the spring characteristic figure (load / displacement graph) of the upright spring of this invention and the conventional horizontal spring. It is a wave form diagram of the free vibration for calculating | requiring the resonance point of the seismic isolation apparatus of the upright spring of this invention. It is a figure (displacement / time graph) which shows the behavior of a base isolation table when an El centro earthquake acts on the base spring isolation device of the present invention. It is a figure which shows that a damper arrangement | positioning is difficult, (b) is a top view of the seismic isolation apparatus in the case of an erecting spring + viscous damper of this invention, (b) is BB cross section of (b) Fig., (C) is a plan view of a conventional seismic isolation device in the case of a horizontal spring and a viscous damper, (d) is a cross-sectional view taken along the line CC of (c), (e) is a cross-sectional view taken along the line BB of (c) Figure. FIG. 2 is a cross-sectional view showing a comparison of the seismic isolation device of the diagonally arranged spring according to the present invention with a seismic isolation device of an upright spring, in which (a) is a cross-sectional view when the spring is upright and has a maximum left displacement; (C) is a cross-sectional view when the spring is upright and has a maximum right displacement, (D) is a cross-sectional view when the spring is diagonally arranged and has a maximum left displacement, and (E) is a neutral position when the spring is diagonally arranged (F) is a cross-sectional view in the case of the right maximum displacement in the spring diagonal arrangement. It is a figure which shows the comparison of the external shape (contour) of the seismic isolation device of the diagonal arrangement | positioning spring of this invention, and the seismic isolation device of an upright spring, (A) is a top view in the case of a spring upright, (B) is the case of a spring upright (C) is a plan view in the case of an oblique spring arrangement, and (d) is a cross-sectional view in the case of an oblique spring arrangement. It is the item map used by the calculation which calculates | requires the spring characteristic of the diagonally arranged spring of this invention. It is a perspective view of the diagonally arranged spring of FIG. It is a top view of the diagonally arranged spring of FIG. It is sectional drawing of the seismic isolation apparatus of this invention at the time of two opposing arrangement | positioning of FIG. FIG. 19 is a specification diagram used in a calculation for obtaining the spring characteristic of the opposed spring in FIG. 18. It is a perspective view of the opposing spring of FIG. It is a top view of the opposing spring of FIG. It is a graph which shows the spring force change (vertical axis) with respect to the tension | pulling direction (horizontal axis, (theta)) in a diagonally arranged spring. It is a graph which shows the change (vertical axis | shaft) of the spring force with respect to the tension | pulling stroke (horizontal axis) in a diagonally arranged spring. It is sectional drawing which shows the amount of offsets and a spring set angle in a diagonally arranged spring. It is a graph which shows the result at the time of changing the amount of offsets from s = 0.1m to s = 0.03m in the diagonally arranged spring, and is a graph showing that it is almost the same as the upright spring regardless of the pulling direction. is there. It is sectional drawing of the conventional gravity type ball-type seismic isolation device. It is sectional drawing of the conventional gravity type | mold linear bearing 2 step | paragraph type seismic isolation apparatus. It is sectional drawing of the conventional spring type and laminated rubber type seismic isolation apparatus. It is sectional drawing of the conventional horizontal spring type seismic isolation apparatus. It is a top view of the conventional horizontal spring type seismic isolation apparatus. It is AA sectional drawing of the horizontal spring type seismic isolation apparatus of FIG. It is an interference check figure of the horizontal spring type seismic isolation device of FIG. It is a graph of the set load / spring length of the horizontal spring type seismic isolation device of FIG. It is a graph which shows that the spring characteristic of the conventional horizontal spring type seismic isolation device has a flaw (the horizontal axis is a pulling direction, and the angle θ is the spring direction). It is a load / displacement figure which shows the spring characteristic when the base isolation table is pulled in the spring attachment direction (0 degree) and the direction without the spring (45 degrees). It is a vibration model conceptual diagram of a spring horizontal arrangement type seismic isolation device. FIG. 37 is a behavior diagram (acceleration waveform diagram) of a base isolation table when the vibration model of FIG. 36 is not supplemented with NS (north-south) waves of the Kobe earthquake. FIG. 37 is a behavior diagram (acceleration waveform diagram) of the base isolation table when the EW (east-west) wave of the El centro earthquake is not supplemented to the vibration model of FIG. 36. FIG. 37 is a behavior diagram (amplitude waveform diagram) of the base isolation table when the vibration model of FIG. 36 is not supplemented with the NS (north-south) wave of the Kobe earthquake. FIG. 37 is a behavior diagram (amplitude waveform diagram) of the base isolation table when the EW (east-west) wave of the El centro earthquake is not supplemented in the vibration model of FIG. 36. It is sectional drawing of a fluid damper. (A) is a sectional view of the viscous damper, and (b) is a half-plan view of the viscous damper of (a). (A) is a plan view of a conventional horizontal spring type seismic isolation device with a viscous damper, (B) is a cross-sectional view taken along the line CC of (A), and (C) is a cross-sectional view taken along the line B-B of (A). It is a figure, (d) is a top view of the conventional horizontal spring type seismic isolation device without a viscous damper, (e) is AA sectional drawing of (d). It is sectional drawing of a friction damper. It is sectional drawing of a rolling friction damper.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Base isolation device 11 Fixing base 12 Base isolation base 13 Ball 14 Spring 15 Spring axis 16 Damper 17 Receptacle

Claims (4)

  A fixed base, a base-isolated base movable in a horizontal direction with respect to the fixed base, a ball arranged between the fixed base and the base-isolated base, one end connected to the base and the other connected to the base-isolated base A seismic isolation device having a spring for returning the base isolation table to the origin position, wherein the spring has a spring axis having an angle of not less than 35 degrees and not more than 90 degrees with respect to the horizontal direction.   The seismic isolation device according to claim 1, wherein the spring has a spring axis having an angle of 90 degrees with respect to a horizontal direction.   The seismic isolation device according to claim 1, wherein the spring has a spring axis having an angle of 35 degrees or more and less than 90 degrees from the horizontal direction.   The seismic isolation device according to claim 1, further comprising a damper.

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