JP3867223B2 - Seismic isolation device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of a seismic isolation device.
[0002]
[Prior art]
In recent years, for display stands and buildings, seismic isolation devices have been placed between the base and the ground to prevent rolling from the base and the ground from being transmitted to the display and the building. There are various proposals for seismic isolation devices.
[0003]
Among them, for example, a seismic isolation device called a ball isolator is positioned above the base plate 2 and a base plate 2 installed horizontally on a base 1 such as a base or ground as shown in FIG. At the same time, it has a main body 4 connected to the seismic isolation body 3 such as a display stand or a building while having a bearing ball B that rolls on the upper surface 2a of the base plate 2.
[0004]
At this time, it is assumed that the upper surface 2a of the base plate 2 is set to a conical concave surface having a linear upward slope at an appropriate angle from the center toward the outer periphery, and this is compared to the case where the so-called upper surface is a curved surface. Consideration is given to avoid resonance when the support ball B rolls on the upper surface 2a.
[0005]
Further, the support ball B is made of a large-diameter steel ball, and as shown in FIG. 4, it is set to have a structure that comes into contact with a group of ball bearings b that are a large number of small-diameter steel balls housed in the main body 4. The rolling performance is guaranteed.
[0006]
That is, the main body 4 includes a ball seat 41, a ball guide 42, and a block 43 that is integrally provided with the ball seat 41 and the ball guide 42 and is connected to the seismic isolation body 3.
[0007]
At this time, the ball seat 41 is formed so as to exhibit a downward substantially funnel-like appearance, and the lower end surface 41a that faces the outer peripheral surface of the support ball B is curved with the same curvature as the curvature of the support ball B. The upper end shaft portion 41 b is pivotally supported by the shaft core portion of the block 43 and can be rotated in the horizontal direction.
[0008]
The ball guide 42 functions as a so-called seat for a ball bearing b to be described later, and also functions as a cover for preventing the ball bearing b from dropping off.
[0009]
On the other hand, the ball bearing b is formed between the support ball B and the ball seat 41 and functions as an effective gap, and between the support ball B and the ball guide so as to be continuous with the concave gap A1. An annular curved gap A2 that is formed and functions as a guide gap, and an annular curved gap A3 that is formed between the block 43 and the ball seat 41 so as to be continuous with the annular curved gap A2 and that functions as a floating gap are filled. It is said that it will be contained.
[0010]
Therefore, in this seismic isolation device, for example, when rolling is developed in the base 1, the bearing ball B rolls up and down the upper surface 2 a of the base plate 2 as viewed relatively. Therefore, the seismic isolation body 3 is prevented from rolling due to the roll of the base 1, that is, the base is isolated.
[0011]
At this time, the ball bearing b group in the concave gap A1 which is an effective gap transmits the load from the upper side to the lower supporting ball B, while the supporting ball B rotates as indicated by an arrow in the figure, for example. When moving, as indicated by the arrows in the figure, it moves toward the annular curved gap A2, which is a guide gap, that is, it flows.
[0012]
Incidentally, when the ball bearing b group flows toward the left annular curved gap A2 in the figure, the ball bearing b from the right annular curved gap A2 in the opposite figure is replenished to the concave gap A1. Will flow into.
[0013]
When the roll of the base 1 disappears, the bearing ball B returns to the center of the upper surface 2a of the base plate 2, and as shown in the figure, when the bearing ball B stops at the center of the upper surface 2a, The body 3 is stabilized in a stationary state.
[0014]
[Problems to be solved by the invention]
However, in the above-described seismic isolation device, it may be pointed out that the load burden due to the ball bearing b group in the concave gap A1 that is an effective gap is not realized as set.
[0015]
That is, in this seismic isolation device, the ball bearing b group in the concave gap A1 is set so as to fulfill the function of transmitting the load from above to the supporting ball B as below.
[0016]
Therefore, when the number of the ball bearings b in the concave gap A1 decreases, it becomes impossible to bear the load as set, that is, the load on each ball bearing b becomes excessive, and the ball bearings b are deformed to be gathered. Or will be destroyed.
[0017]
If the ball bearings b that are crowded are deformed or broken, the rolling of the bearing ball B cannot be guaranteed, and therefore the seismic isolation device cannot be used as a seismic isolation device.
[0018]
By the way, it can be considered that the decrease in the number of the ball bearings b described above occurs in the conventional seismic isolation device described above for the following reason.
[0019]
That is, as shown in FIG. 5, the lower end on the outer peripheral side of the ball seat 41 forms the above-described annular curved gap A2, and also forms a joining portion between the annular curved gap A2 and the concave gap A1.
[0020]
At this time, the annular curved gap A2 has a gap width larger than the diameter of the bearing b in order to prevent the ball bearing b here from being pressed against the ball guide 42 at the lower end of the ball seat 41 and becoming unable to move. Is set to
[0021]
Incidentally, the lower end on the outer peripheral side of the ball seat 41 is set to a curved surface made of a circle having the same diameter as the wall thickness for the purpose of finishing this into a so-called curved surface.
[0022]
On the other hand, in the ball guide 42, the portion that forms the above-mentioned merging portion is a horizontal surface portion 42a that is an annular flat portion for reasons of processing.
[0023]
Therefore, when the ball bearing b1 on the horizontal surface portion 42a comes into contact with the lower end surface 41a of the ball seat 41, that is, when the ball bearing b2 moves to the so-called inlet of the concave gap A1 where the ball bearing b2 is located, there is a considerable amount. It is required to increase the stroke H.
[0024]
In addition, the ball bearing b shown with a broken line in the drawing indicates a locus when the ball bearing b1 moves to the position of the ball bearing b2.
[0025]
As a result, the ball bearing b1 on the horizontal plane portion 42a must increase the stroke H by a load from the ball bearings b in the annular curved gaps A2 and A3 which are above the rear side. In addition, there is a limit to the load from the ball bearing b group in the annular curved gaps A2 and A3. Therefore, the load cannot be easily moved to the entrance of the concave gap A1, and should be in the concave gap A1 as an effective gap. It is thought that the number of ball bearings b group will decrease.
[0026]
The present invention was devised in view of the above-described circumstances, and the object of the invention is to enable a load bearing as set by a ball bearing group that transmits a load from above to a bearing ball that is below. It is to provide a seismic isolation device that can sufficiently achieve the intended purpose.
[0027]
[Means for Solving the Problems]
In order to achieve the above object, the means of the present invention includes: A base plate, a support ball provided on the upper surface of the base plate so as to be freely rollable, a block which is provided on the side of the seismic isolation body and faces the base plate, a substantially funnel-shaped ball seat provided at the center of the block, and a block A ball guide that is provided in a lower portion of the ball seat so as to face the ball seat and rotatably accommodates the bearing ball, and a first bearing formed between a curved bearing surface at the center of the lower end of the ball seat and an outer surface of the bearing ball. A curved concave gap, a second curved gap formed between the curved surface on the outer periphery of the lower end of the ball sheet and the upper surface of the ball guide, and the curved curvature of the ball sheet. A third curved gap formed between the upper side face and the curved lower center face of the block and continuing to the second curved gap, and a plurality of rolls interposed in the gaps. In the seismic isolation device, in which the horizontal surface portion is formed on the inner peripheral upper surface of the ball guide that forms the second curved gap, the first lower end outer peripheral curved surface of the ball seat The other horizontal plane portion parallel to the horizontal plane portion of the ball guide is extended toward the concave clearance direction of 1 to be continuous with the bearing surface of the ball seat.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on the illustrated embodiment. However, even in the seismic isolation device according to the present invention, basically, the seismic isolation device shown in FIGS. 4 and 5 described above is basically used. This is a seismic isolation device called a so-called ball isolator.
[0029]
Therefore, in the illustrated embodiment, where the configuration is the same as in the case of the conventional example described above, the same reference numerals are given in the drawing, and detailed description thereof is omitted unless necessary. The following description will focus on the features of the present invention.
[0030]
That is , the new seismic isolation device according to the present invention is connected to the base plate 2, the support ball B provided on the upper surface 2a of the base plate 2 so as to be able to roll, and the seismic isolation body 3 side, as in the conventional example of FIG. A block 43 that faces the base plate 2, a substantially funnel-shaped ball sheet 41 provided in the center of the block 43, a lower part of the block 43 that faces the ball sheet 41, and the support ball B A ball guide 42 rotatably accommodated, a first curved concave gap A1 formed between the curved bearing surface 41 a at the center of the lower end of the ball sheet 41 and the outer surface of the bearing ball B, and the ball sheet 41 And a curved upper side of the ball seat 41, which is formed between the curved surface on the outer periphery of the lower end of the ball and the upper surface of the ball guide 42 and continues to the first concave gap A1. Is formed between the curved central bottom surface of the block 43 and the third bending gap A3 of continuing to the second curved gap A2, it is rollably interposed above the gaps A1, A2, the A3 and Further, a horizontal plane portion 42 a is formed on the inner peripheral side upper surface of the ball guide 42 that forms the second curved gap A <b> 2 and a large number of ball bearings b .
In the present invention, as shown in FIGS . 1 and 2, the ball seat 41 is parallel to the horizontal surface portion 42a of the ball guide 42 from the curved surface at the outer periphery on the lower end toward the first concave gap A1. The other horizontal surface portion 41c is extended to be continuous with the bearing surface 41a of the ball seat 41.
This will be described in more detail below.
[0031]
Therefore, in the case of this embodiment, compared to the case of the conventional example described above, the outer circumferential side of the concave gap A1 that is an effective gap formed between the support ball B and the lower end surface 41a that is a curved concave surface. The end will become longer downward.
[0032]
That is, in the case of the conventional example, the lower end edge of the lower end surface 41a, which is a curved concave surface, is a position indicated by reference numeral c1 in the figure, that is, the tangential position of the circle forming the lower end on the outer peripheral side of the ball seat 41. This is the point of intersection of a line connecting the center of the circle and the center of the support ball B (see FIG. 5).
[0033]
On the other hand, in the case of this embodiment, the horizontal surface portion 41c is formed so as to be along the tangential direction of the horizontal direction of the circle forming the lower end on the outer peripheral side of the ball seat 41. The point position c between the lower end edge of the end surface 41a and the inner peripheral side edge of the horizontal surface portion 41c is lower than the above-described point position c1.
[0034]
At this time, the line connecting the center of the support sphere B and the meeting point position c has a so-called wide angle than the line connecting the center of the support ball B and the meeting point position c1.
[0035]
From the above, the so-called entrance of the concave gap A1 according to this embodiment approaches the horizontal surface portion 42a formed on the ball guide 42. Therefore, the ball shown by the broken line in the figure on the horizontal surface portion 42a. It is sufficient that the bearing b rises by a small stroke h as far as the position where the ball bearing b shown by the solid line in the figure is located, that is, the entrance to the concave gap A1 as compared with the conventional example. become.
[0036]
As a result, the ball bearing b on the horizontal surface portion 42a can increase the stroke h by a load from the ball bearing b group in the annular curved gaps A2 and A3 which are above the rear side. Thus, it can be easily moved to the entrance of the concave gap A1.
[0037]
Moreover, since the outer peripheral side end of the concave gap A1 becomes longer downward, the effective gap as the concave gap A1 becomes wider, and therefore the number of ball bearings b accommodated therein increases.
[0038]
At this time, in this embodiment, it is only necessary to make a slight design change to the lower end of the ball seat 41, and it is not necessary to increase the overall length of the ball seat 41, which is advantageous in that the implementation is easy. Become.
[0039]
And, by increasing the number of ball bearings b in the concave gap A1, the load borne by each ball bearing b is reduced, and therefore, the ball bearings b gathering in the concave gap A1 are less likely to be deformed or broken, Speaking of the rolling of the support ball B, it can be guaranteed permanently.
[0040]
FIG. 2 is an enlarged view of the lower end of the above-described ball seat 41. The continuous position between the inner peripheral side edge of the horizontal surface portion 41c and the lower end edge of the lower end surface 41a, which is a curved concave surface, is indicated by c in the figure. In the drawing, it is formed so as to have a so-called angle, but instead of this, as shown by a broken line diagram in the drawing, a small radius may be attached to this continuous position.
[0041]
In this case, a smooth flow of the ball bearing b can be expected as compared with a case where the continuous position is so-called angular, and therefore, the number of effective ball bearings b in the concave gap A1 can be ensured. This is advantageous.
[0042]
【The invention's effect】
As described above, according to the present invention, the conventional seismic isolation device is improved to be parallel to the horizontal surface portion of the ball guide from the curved surface on the outer peripheral side of the lower end of the ball seat toward the first concave clearance. Since the horizontal surface of the ball seat is extended to be continuous with the bearing surface of the ball seat, the concave gap, which is an effective gap through which a large number of ball bearings are interposed, can be extended so that the outer peripheral side ends downward. The ball bearing on the horizontal surface of the ball guide that will be adjacent to the inlet of the ball can easily move to the inlet of the concave gap by raising a small stroke.
[0043]
Further, since the outer peripheral side end of the concave gap becomes longer downward, the effective gap as the concave gap becomes wider, and therefore the number of ball bearings accommodated therein increases.
[0044]
At this time, according to the present invention, only a slight design change is made to the lower end of the ball seat, and the ball seat is not increased in overall length, and is therefore advantageous in that its implementation becomes easy. It becomes.
[0045]
As the number of ball bearings in the concave gap increases, the load borne by each ball bearing is reduced, and therefore the ball bearings crowded in the concave gap are less likely to be deformed or broken, and It can be guaranteed permanently.
[0046]
As a result, according to the present invention, in the seismic isolation device called a ball isolator, the ball bearing group for transmitting the load from above to the bearing ball below is set as well as the load load beyond that. It is possible to achieve the intended purpose sufficiently while making it possible, and it is optimal to expect the improvement of its versatility without incurring the unreasonable cost increase in its implementation. There is.
[Brief description of the drawings]
FIG. 1 is a partial explanatory view schematically showing a main part of a seismic isolation device according to the present invention.
FIG. 2 is a partial explanatory view showing the main part in FIG. 1 further enlarged;
FIG. 3 is an overall view showing a seismic isolation device as a conventional example in partial cross section.
4 is an enlarged longitudinal sectional view showing the seismic isolation device of FIG. 3. FIG.
5 is a view showing the main part of the seismic isolation device of FIG. 4 in the same manner as FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Base 2 Base plate 2a Upper surface 3 Seismic base 4 Body part 41 Ball seat 41a Lower end surface 41b Upper end shaft part 41c, 42a Horizontal surface part 42 Ball guide 43 Block A1 Concave gap A2, A3 Annular curved gap B Bearing ball b, b1, b2 Ball bearing

Claims (1)

A base plate, a support ball provided on the upper surface of the base plate so as to be freely rollable, a block which is provided on the side of the seismic isolation body and faces the base plate, a substantially funnel-shaped ball seat provided at the center of the block, and a block A ball guide that is provided in a lower portion of the ball seat so as to face the ball seat and rotatably accommodates the bearing ball, and a first bearing formed between a curved bearing surface at the center of the lower end of the ball seat and an outer surface of the bearing ball. A curved concave gap, a second curved gap formed between the curved surface on the outer periphery of the lower end of the ball sheet and the upper surface of the ball guide, and the curved curvature of the ball sheet. A third curved gap formed between the upper side surface and the curved central lower surface of the block and continuing to the second curved gap; and a plurality of rolling gaps interposed in the gaps. In the seismic isolation device, in which the horizontal surface portion is formed on the inner peripheral upper surface of the ball guide that forms the second curved gap, the first lower end outer peripheral curved surface of the ball seat 1. A seismic isolation device characterized by extending another horizontal plane portion parallel to the horizontal plane portion of the ball guide toward the concave clearance direction of 1 to be continuous with the bearing surface of the ball seat.

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