Dampers and buildings

Abstract

To realize a damper capable of coping with both small and large earthquakes.SOLUTION: A damper (1) comprises: a piston (20) that is displaceable relative to a cylinder (10) filled with fluid; a communication pipe (30) through which the fluid flows as the piston displaces; a first weight (50) that rotates in response to the rotation of a rotor (40) caused by the flow of the fluid in the communication pipe; and an inertia moment variation mechanism (60) that varies the inertia moment of the first weight in response to the movement of the piston.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a damper and a building provided with the damper.

Background Art

[0002] As a means for reducing the influence of an earthquake on a building, providing a seismic isolation device can be mentioned. The seismic isolation device includes an isolator that reduces the acceleration of the building and a damper that reduces the displacement of the building. Examples of dampers are disclosed in Patent Documents 1 and 2.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Generally, in a small-scale earthquake, reduction of the acceleration of the building is emphasized. On the other hand, in a large-scale earthquake, reduction of the displacement of the building is emphasized. However, with the dampers disclosed in Patent Documents 1 and 2, it has been difficult to achieve both reduction of the acceleration of the building and reduction of the displacement. That is, it has been difficult to sufficiently cope with both small-scale earthquakes and large-scale earthquakes.

[0005] One aspect of the present invention aims to realize a damper or the like that can cope with both small-scale earthquakes and large-scale earthquakes.

Means for Solving the Problems

[0006] To solve the above problems, a damper according to one aspect of the present invention comprises a cylinder filled with fluid, a piston displaceable relative to the cylinder that divides the inside of the cylinder into a first chamber and a second chamber, a connecting pipe that connects the first chamber and the second chamber and allows the fluid to flow from the first chamber to the second chamber or from the second chamber to the first chamber as the piston is displaced, a rotating body provided in the middle of the connecting pipe and rotating due to the flow of the fluid in the connecting pipe, and a first weight that rotates in conjunction with the rotation of the rotating body, wherein the moment of inertia of the first weight changes according to the operation of the piston. [Effects of the Invention]

[0007] According to one aspect of the present invention, it is possible to realize dampers and the like that can respond to both small and large earthquakes. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view showing the structure of a building according to Embodiment 1. [Figure 2] This is a plan view of the damper according to Embodiment 1, as seen from vertically above. [Figure 3] This is a side view of the damper according to Embodiment 1, as seen from the horizontal direction. [Figure 4] This is a schematic diagram of a damper according to Embodiment 1. [Figure 5] This figure shows an example of the operation of the moment of inertia fluctuation mechanism according to Embodiment 1. [Figure 6] This figure shows an example of the operation of the moment of inertia fluctuation mechanism according to Embodiment 1. [Figure 7] This graph shows an example of the response magnification of the damper according to Embodiment 1 when the building displacement is small. [Figure 8] This graph shows an example of the response magnification of the damper according to Embodiment 1 when the building displacement is small. [Figure 9] This graph shows an example of the response magnification of the damper according to Embodiment 1 when the building displacement is large. [Figure 10]It is a graph showing an example of the response magnification factor of the damper according to Embodiment 1 when the displacement of the building is large. [Figure 11] It is a diagram showing an example of the operation of the moment of inertia variation mechanism according to a modification of Embodiment 1. [Figure 12] It is a diagram showing an example of the operation of the moment of inertia variation mechanism according to a modification of Embodiment 1. [Figure 13] It is a diagram showing an example of the operation of the moment of inertia variation mechanism according to Embodiment 2. [Figure 14] It is a diagram showing an example of the operation of the moment of inertia variation mechanism according to Embodiment 2. [Figure 15] It is a diagram showing an example of the operation of the moment of inertia variation mechanism according to Embodiment 3. [Figure 16] It is a diagram showing an example of the operation of the moment of inertia variation mechanism according to Embodiment 3.

Best Mode for Carrying Out the Invention

[0009] [[ID=2']6]〔Embodiment 1〕 Hereinafter, an embodiment of the present invention will be described in detail. In each drawing, two directions orthogonal to each other in the horizontal plane are taken as the X direction and the Y direction, and the vertical direction is taken as the Z direction. Also, in each drawing, for the sake of simplicity, there are cases where only a part of a plurality of members to which the same reference numerals should be attached is provided with the reference numerals.

[0010] FIG. 1 is a cross-sectional view showing the configuration of a building 100 according to Embodiment 1. As shown in FIG. 1, the building 100 includes a damper 1, a first structure 110, a second structure 120, and an elastic body 150. The first structure 110 is a foundation on which the building is installed. The second structure 120 is a building installed on the first structure 110.

[0011] The damper 1 attenuates vibrations transmitted from the first structure 110 to the second structure 120 due to an earthquake or the like. The specific configuration of the damper 1 will be described later.

[0012] The elastic body 150 is an isolator that mitigates vibrations transmitted from the first structure 110 to the second structure 120 due to earthquakes or the like. The elastic body 150 is connected in series with the damper 1. The elastic body 150 may be, for example, rubber or a spring.

[0013] The elastic body 150 is flexible compared to the first structure 110 and the second structure 120. The elastic constant of the elastic body 150 may be, for example, half or less of the elastic constant of the damper 1.

[0014] FIG. 2 is a plan view of the damper 1 as viewed from vertically above. FIG. 3 is a side view of the damper 1 as viewed from the horizontal direction. FIG. 4 is a schematic diagram of the damper 1. In FIG. 4, the damper 1 is illustrated by combining a plan view and a cross-sectional view. The configuration of the damper 1 will be described below with reference to FIGS. 2 to 4. As shown in FIGS. 2 to 4, the damper 1 includes a cylinder 10, a piston 20, a communication pipe 30, a rotating body 40, a first weight 50, and an inertia moment fluctuation mechanism 60. The damper 1 also includes a rod 25.

[0015] The cylinder 10 is a cylindrical member filled with a fluid. The type of fluid can be used without particular limitation, such as hydraulic oil used in general dampers. The cylinder 10 has a first chamber 11 and a second chamber 12. In the following description, it is assumed that in the cylinder 10, the first chamber 11 is located on the side of the first structure 110, and the second chamber 12 is located on the side of the second structure 120. Also, the axial direction of the cylinder 10 is defined as the X direction.

[0016] The piston 20 divides the inside of the cylinder 10 into the first chamber 11 and the second chamber 12. The piston 20 is displaceable with respect to the cylinder 10. Therefore, as the piston 20 is displaced, the volumes of the first chamber 11 and the second chamber 12 fluctuate.

[0017] The rod 25 penetrates the cylinder 10 and the piston 20 in the axial direction of the cylinder 10. One end of the rod 25 is connected to the second structure 120. Therefore, when vibration is transmitted from the first structure 110 to the second structure 120, the rod 25 is displaced relative to the cylinder 10.

[0018] The rod 25 is slidable relative to the cylinder 10 at both ends of the cylinder 10. Therefore, the fluid filled in the cylinder 10 does not flow out of the first chamber 11 and the second chamber 12 from around the rod 25.

[0019] The cylinder 10 further has a rod chamber 15. The rod chamber 15 is located closer to the first structure 110 than the first chamber 11. The rod chamber 15 accommodates the other end of the rod 25 that protrudes from the first chamber 11 towards the first structure 110.

[0020] The rod 25 is integrally formed with the piston 20, passing through the piston 20 in the axial direction of the cylinder 10. Therefore, when the rod 25 is displaced relative to the cylinder 10, the piston 20 is also displaced relative to the cylinder 10.

[0021] The connecting pipe 30 connects the first chamber 11 and the second chamber 12. The connecting pipe 30 allows fluid to flow from the first chamber 11 to the second chamber 12, or from the second chamber 12 to the first chamber 11, as the piston 20 is displaced.

[0022] The rotating body 40 rotates due to the fluid flow in the connecting pipe 30. The rotating body 40 is installed in the middle of the connecting pipe 30. The rotating body 40 may, but is not limited to, a gear motor that rotates due to the fluid flow.

[0023] The first weight 50 rotates in conjunction with the rotation of the rotating body 40. The first weight 50 may rotate integrally with, for example, the rotation axis 40a of the rotating body 40. That is, the rotation axis 40a of the rotating body 40 and the rotation axis 50a of the first weight 50 may be the same. However, the first weight 50 is not limited to this, and may rotate around another rotation axis that rotates in conjunction with the rotation of the rotation axis 40a of the rotating body 40. Also, although there are four first weights 50 in Figure 2, there may be three or fewer first weights 50, or five or more first weights 50.

[0024] The axis of rotation 50a of the rotational motion of the first weight 50 may be parallel to the vertical direction (Z-axis direction). In this case, the effect of gravity on the direction of movement in the rotational motion of the first weight 50 is constant regardless of the position of the first weight 50, thereby stabilizing the operation of the damper 1.

[0025] The moment of inertia variation mechanism 60 supports the first weight 50 in such a way that its moment of inertia around the rotation axis 50a can be changed. The moment of inertia variation mechanism 60 may rotate together with the rotating body 40 and the first weight 50 around the rotation axes 40a, 50a as the rotating body 40 rotates. In damper 1, the moment of inertia variation mechanism 60 changes the moment of inertia of the first weight 50 in accordance with the movement of the piston 20. The movement of the piston 20 refers to, for example, the position or displacement velocity of the piston 20. The position and displacement velocity of the piston 20 differ depending on the magnitude of the displacement of the second structure 120 relative to the first structure 110 due to the earthquake, i.e., the magnitude of the earthquake. Therefore, the moment of inertia of the first weight 50 fluctuates according to the magnitude of the earthquake.

[0026] In damper 1, the moment of inertia of the first weight 50 changes as the radius of rotation of the first weight 50 changes. Here, the radius of rotation of the first weight 50 is the length from the center 67 of the first weight 50 of the tension member 61 to the axis of rotation 50a on which the first weight 50 rotates. Specifically, in damper 1, the first weight 50 is displaceable along the radial direction of its own rotational motion. The moment of inertia fluctuation mechanism 60 displaces the first weight 50 along the radial direction. This makes it possible to make the characteristics of damper 1 different in accordance with the operation of the piston 20.

[0027] Figures 5 and 6 show examples of the operation of the moment of inertia fluctuation mechanism 60. Figure 5 shows the moment of inertia fluctuation mechanism 60 when the displacement of the piston 20 is small, and Figure 6 shows the moment of inertia fluctuation mechanism 60 when the displacement of the piston 20 is large.

[0028] In the examples shown in Figures 5 and 6, the moment of inertia of the first weight 50 changes as the radius of rotation of the first weight 50 changes in accordance with the displacement of the piston 20, thereby changing the moment of inertia of the first weight 50. The moment of inertia of the first weight 50 includes a tension member 61, a direction changing member 62, and a cam mechanism 63. The tension member 61 and the direction changing member 62 rotate in conjunction with the rotational motion of the first weight 50.

[0029] The tension member 61 is a member that extends from the first weight 50 in a first direction. The first direction is a direction that is not parallel to the rotation axis 50a of the first weight 50. The tension member 61 may be, for example, a wire. The direction changing member 62 is a member that changes the direction in which the tension member 61 extends from the first direction to the second direction. The direction changing member 62 may be, for example, a pulley or a member having an arc-shaped wire path. Here, the point at which the tension member 61 changes from the first direction to the second direction by the direction changing member 62 is called the direction changing point 62a.

[0030] In the following description, the first direction is assumed to be horizontal and directed from the first weight 50 towards the axis of rotation 50a of the first weight 50, and the second direction is assumed to be vertical. However, the first and second directions in damper 1 are not necessarily limited to these.

[0031] The cam mechanism 63 causes the distance between the tension member 61, at the end 61b opposite to the end 61a connected to the first weight 50, and the direction change point 62a to change in accordance with the displacement of the piston 20 relative to the cylinder 10. In other words, the cam mechanism 63 causes the distance between the tension member 61, at the end 61a connected to the first weight 50, and the direction change point 62a to change in accordance with the displacement of the piston 20 relative to the cylinder 10. The cam mechanism 63 includes a guide portion 64 and a guided portion 65.

[0032] The guide portion 64 is a member that extends in one direction in the horizontal plane. The guided portion 65 is a member that has a shape that allows it to move along the guide portion 64. The other end 61b of the tension member 61 described above is connected to the guided portion 65. For example, the guided portion 65 may be a cylindrical rotating member that can move along the guide portion 64 while rotating. In this case, the other end 61b of the tension member 61 is connected to the rotating member that serves as the guided portion 65. However, the configuration of the guided portion 65 is not limited to this.

[0033] The guide portion 64 is fixed to the second structure 120. The position of the guided portion 65 in the horizontal plane is fixed to the cylinder 10. Therefore, when vibration is transmitted from the first structure 110 to the second structure 120, the guide portion 64 is displaced relative to the guided portion 65.

[0034] The guide section 64 has a first region 64a and second regions 64b located on both sides of the first region 64a when viewed from a vertical plane. The height of the upper edge 66a of the guide section 64 in the first region 64a is higher than the height of the upper edge 66b of the guide section 64 in the second region 64b. In other words, the edge 66a of the first region 64a opposite to the first weight 50 is further away from the first weight 50 than the edge 66b of the second region 64b opposite to the first weight 50. The distance between the guided section 65 and the guided section 65 varies depending on whether the guided section 65 is located in the first region 64a or the second region 64b of the guide section 64.

[0035] Here, the sum of the distance from the first weight 50 to the direction change point 62a and the distance from the direction change point 62a to the guided section 65 is always approximately constant. Therefore, if the height of the guided section 65 changes, the distance from the first weight 50 to the direction change point 62a changes, and the turning radius of the first weight 50 also changes.

[0036] When the vibration transmitted from the first structure 110 to the second structure 120 is small, the displacement of the guide 64 relative to the guided portion 65 is also small. In this case, as shown in Figure 5, the guided portion 65 is located on the first region 64a. On the other hand, when the vibration transmitted from the first structure 110 to the second structure 120 is large, the displacement of the guide 64 relative to the guided portion 65 is larger compared to the case when the vibration transmitted from the first structure 110 to the second structure 120 is small. In this case, as shown in Figure 6, the guide 64 is located off the first region 64a and on the second region 64b. The guided portion 65 may also be located between the first region 64a and the second region 64b (on the sloping surface of the guide 64). The slope of the sloping surface of the guide 64 may be made gentler so that the guided portion 65 is continuously displaced on the sloping surface.

[0037] When the vibration transmitted from the first structure 110 to the second structure 120 is large, the height of the guided portion 65 becomes lower compared to when the vibration transmitted from the first structure 110 to the second structure 120 is small. As a result, the distance from the guided portion 65 to the direction change point 62a becomes shorter, and the distance from the first weight 50 to the direction change point 62a becomes longer. Consequently, when the vibration transmitted from the first structure 110 to the second structure 120 is large, the rotation radius and moment of inertia of the first weight 50 become larger compared to when the vibration transmitted from the first structure 110 to the second structure 120 is small.

[0038] Furthermore, when the vibration transmitted from the first structure 110 to the second structure 120 is small, the displacement of the piston 20 relative to the cylinder 10 is also small. On the other hand, when the vibration transmitted from the first structure 110 to the second structure 120 is large, the displacement of the piston 20 relative to the cylinder 10 is larger compared to when the vibration transmitted from the first structure 110 to the second structure 120 is small. Therefore, it can be said that the moment of inertia of the first weight 50 changes in accordance with the displacement of the piston 20.

[0039] (Damper characteristics) One indicator of a damper's characteristics is the response ratio. The response ratio is the ratio of the response value to the input seismic wave. In small earthquakes, it is important to reduce the response ratio for building acceleration in order to reduce deterioration of habitability. On the other hand, in large earthquakes, it is important to reduce the response ratio for building displacement in order to reduce damage to the building.

[0040] Generally, the natural period of displacement in buildings is about 4 seconds. On the other hand, the natural period of acceleration is about 2 to 3 seconds, which is different from the natural period of displacement. For this reason, dampers with constant characteristics regardless of earthquake magnitude have difficulty handling both the response factor for acceleration in small earthquakes and the response factor for displacement in large earthquakes.

[0041] The characteristics of damper 1 vary depending on the moment of inertia of the first weight 50. As mentioned above, the moment of inertia of the first weight 50 varies depending on the magnitude of the earthquake. Therefore, the characteristics of damper 1 vary depending on the magnitude of the earthquake.

[0042] Figures 7 and 8 are graphs showing examples of response magnification in a building when the building displacement is small. Figure 7 is a graph for building displacement, and Figure 8 is a graph for building acceleration. Figures 9 and 10 are graphs showing examples of response magnification in a building when the building displacement is large. Figure 9 is a graph for building displacement, and Figure 10 is a graph for building acceleration. In each graph, the horizontal axis is the period (seconds), and the vertical axis is the response magnification. In each graph, the solid line shows the response magnification of a building 100 equipped with damper 1, and the dashed line shows the response magnification of a building without damper.

[0043] In the graph of Figure 8, which shows the response magnification to acceleration when the building displacement is small, the region with a period of approximately 2 to 3 seconds is enclosed by a dashed line. In this region, it can be seen that the response magnification of building 100 equipped with damper 1 is suppressed to a similar extent as that of building without damper. Therefore, it can be said that damper 1 is able to suppress acceleration with a period of approximately 2 to 3 seconds when the building displacement is small.

[0044] In the graph of Figure 9, which shows the response magnification to displacement when the building displacement is large, the region with a period of about 4 seconds is enclosed by a dashed line. In this region, it can be seen that the response magnification of building 100 equipped with damper 1 is reduced compared to building without damper. Therefore, it can be said that damper 1 is able to reduce displacement with a period of about 4 seconds when the building displacement is large. In this embodiment, the regions with periods of about 2 to 3 seconds and about 4 seconds are shown. However, the present invention is not limited to these, and it is possible to design dampers that match the natural period of the building.

[0045] As described above, Damper 1 is capable of responding to both small and large earthquakes. Such effects contribute to achieving, for example, United Nations Sustainable Development Goal (SDG) 11, "Make cities and human settlements inclusive, safe, resilient and sustainable."

[0046] (modified version) Figures 11 and 12 show examples of the operation of the moment of inertia fluctuation mechanism 60A according to a modified embodiment of Embodiment 1. The moment of inertia fluctuation mechanism 60A differs from the moment of inertia fluctuation mechanism 60 in that the guide portion 64 further comprises a third region 64c in addition to the first region 64a and the second region 64b.

[0047] The third region 64c is located on the opposite side of the first region 64a from the second region 64b, which is located on both sides of the first region 64a. The height of the upper edge of the guide portion 64 in the third region 64c is even lower than the height of the upper edge of the guide portion 64 in the second region 64b.

[0048] In the moment of inertia fluctuation mechanism 60A, when the vibration transmitted from the first structure 110 to the second structure 120 is small, the guided portion 65 is located in the first region 64a, as shown in Figure 11. When the vibration transmitted from the first structure 110 to the second structure 120 becomes large, the guided portion 65 is located in the second region 64b, as shown in Figure 12.

[0049] In the moment of inertia fluctuation mechanism 60A, as the vibration transmitted from the first structure 110 to the second structure 120 increases further, the guided portion 65 is located in the third region 64c. When the guided portion 65 is located in the third region 64c, its height becomes even lower than when it is located in the second region 64b. As a result, the distance from the guided portion 65 to the direction change point 62a becomes even shorter, and the distance from the first weight 50 to the direction change point 62a becomes even longer. Consequently, the rotation radius and moment of inertia of the first weight 50 become even larger.

[0050] As described above, the moment of inertia fluctuation mechanism 60A allows the moment of inertia of the first weight 50 to be changed in three stages according to the amount of displacement of the piston 20 relative to the cylinder 10. Therefore, the moment of inertia of the first weight 50 can be adjusted more precisely according to the magnitude of the earthquake. Furthermore, by changing the shape of the guide portion 64 as needed, the moment of inertia of the first weight 50 can be changed in four or more stages according to the amount of displacement of the piston 20 relative to the cylinder 10. In other words, the damper of the present invention allows for multi-stage adjustment.

[0051] [Embodiment 2] Other embodiments of the present invention are described below. For the sake of clarity, components having the same function as those described in the above embodiments will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0052] Figures 13 and 14 show examples of the operation of the moment of inertia fluctuation mechanism 70 according to Embodiment 2. As shown in Figures 13 and 14, the moment of inertia fluctuation mechanism 70 includes a biasing member 75. The moment of inertia fluctuation mechanism 70 also includes a tension member 71, a direction changing member 72, a binding part 73, and a frame 74. The tension member 71 and the direction changing member 72 are the same as the tension member 61 and the direction changing member 62 in the moment of inertia fluctuation mechanism 60. Here, the point at which the tension member 71 changes from a first direction to a second direction by the direction changing member 72 is called the direction changing point 72a.

[0053] The binding portion 73 is a member to which the other end 71b of the tension member 71, opposite to the end 71a connected to the first weight 50, is connected. The binding portion 73 has a main shaft 73a, a connecting portion 73b provided on one end of the main shaft 73a to which the tension member 71 is connected, and a spring receiving portion 73c provided on the other end of the main shaft 73a. At least one of the connecting portion 73b and the spring receiving portion 73c is detachable from the main shaft 73a.

[0054] The frame 74 is a structure fixed to the cylinder 10. The frame 74 has a hole through which the main shaft 73a of the fastening portion 73 can be inserted. The fastening portion 73 can be attached to the frame 74 by removing the detachable parts of the fastening portion 73b and spring receiving portion 73c from the main shaft 73a, inserting the main shaft 73a into the hole, and then reattaching the detachable parts.

[0055] The fastening portion 73, while attached to the frame 74, is displaceable in a direction along the main shaft 73a within the range defined by the connecting portion 73b and the spring receiving portion 73c. ​​The direction along the main shaft 73a is parallel to the rotational direction of the rotational motion of the first weight 50 when the fastening portion 73 is attached to the frame 74.

[0056] The biasing member 75 biases the first weight 50 in a direction that reduces the radius of rotation of the first weight 50. The biasing member 75 is located between the frame 74 and the spring receiving portion 73c of the main shaft 73a, which is inserted through the frame 74. Specifically, the biasing member 75 biases the binding portion 73 in a direction that moves it away from the frame 74. In other words, in the second direction in which the direction in which the tension member 71 extends is changed by the direction changing member 72, the biasing member 75 biases the other end 71b of the tension member 71 and the direction changing point 72a to increase the distance between them.

[0057] When the vibration transmitted from the first structure 110 to the second structure 120 is small, the centrifugal force generated by the rotation of the first weight 50 is small. In this case, as shown in Figure 13, the rotation radius of the first weight 50 is small due to the elastic force of the biasing member 75.

[0058] On the other hand, as the vibration transmitted from the first structure 110 to the second structure 120 increases, the centrifugal force generated by the rotation of the first weight 50 also increases. That is, as the displacement velocity of the piston 20 increases, the centrifugal force of the first weight 50 also increases. In this case, as shown in Figure 14, the biasing member 75 is compressed by the centrifugal force of the first weight 50, and the radius of rotation of the first weight 50 increases. Consequently, the moment of inertia of the first weight 50 also increases.

[0059] As described above, the moment of inertia of the first weight 50 can also be changed in accordance with the displacement of the piston 20 by the moment of inertia variation mechanism 70. Therefore, even when the damper 1 is equipped with the moment of inertia variation mechanism 70 instead of the moment of inertia variation mechanism 60, it can cope with both small and large earthquakes.

[0060] (modified version) The configuration of the moment of inertia fluctuation mechanism 70 is not limited to the examples shown in Figures 13 and 14. For example, the moment of inertia fluctuation mechanism 70 may include separate biasing members 75 connected to each of the first weights 50. In this configuration, as the centrifugal force generated by the rotation of the first weights 50 increases, the respective biasing members 75 are stretched by the centrifugal force, and the radius of rotation and moment of inertia of the first weights 50 increase.

[0061] Furthermore, if the moment of inertia fluctuation mechanism 70 includes biasing members 75 connected to each of the first weights 50, the biasing members 75 may be located outside the rotational motion of the first weights 50, rather than inside. Moreover, if the moment of inertia fluctuation mechanism 70 includes biasing members 75 connected to each of the first weights 50, the moment of inertia fluctuation mechanism 70 does not need to include a tensioning member 71.

[0062] Furthermore, the moment of inertia fluctuation mechanism 70 may further include a stopper 76 that defines the minimum value of the rotation radius of the first weight 50. The stopper 76 can define the minimum value of the moment of inertia of the first weight 50.

[0063] In this case, the configuration of the moment of inertia fluctuation mechanism 70 is not limited to one that includes a biasing member 75. For example, instead of the biasing member 75, the moment of inertia fluctuation mechanism 70 may further include a weight separate from the first weight 50, which is connected to a tensioning member 71 and applies a force to the first weight 50 in a direction that reduces the rotation radius of the first weight 50. The stopper 76 restricts the movement of the first weight 50 so that the rotation radius of the first weight 50 does not become smaller than a minimum value due to the force applied to the first weight 50 by the tensioning member 71. The minimum value should be set considering the mass and number of the first weights 50, as well as the viscosity of the fluid in the cylinder 10, so that the response ratio of the damper 1 to the acceleration of the building due to a small earthquake becomes sufficiently small. In this configuration as well, as the centrifugal force generated by the rotation of the first weight 50 increases, the rotation radius and moment of inertia of the first weight 50 increase.

[0064] [Embodiment 3] Figures 15 and 16 show examples of the operation of the moment of inertia fluctuation mechanism 80 according to Embodiment 3. Figure 15 shows the moment of inertia fluctuation mechanism 80 when the displacement of the piston 20 is small, and Figure 16 shows the moment of inertia fluctuation mechanism 80 when the displacement of the piston 20 is large.

[0065] In the example shown in Figures 15 and 16, the moment of inertia fluctuation mechanism 80 includes a second weight 81 in addition to the configuration of the moment of inertia fluctuation mechanism 60. For simplicity, the cam mechanism 63 of the configuration of the moment of inertia fluctuation mechanism 60 is omitted in Figures 15 and 16.

[0066] The second weight 81 is located outside the first weight 50 in the radial direction of the first weight 50's rotation. The second weight 81 is rotatable around the rotation axis 50a of the first weight 50. The second weight 81 does not rotate when the rotation radius of the first weight 50 is the first rotation radius. However, the second weight 81 rotates along with the rotation of the first weight 50 when the rotation radius of the first weight 50 is a second rotation radius which is larger than the first rotation radius. Therefore, the overall change in the moment of inertia of

[0067] Specifically, the moment of inertia fluctuation mechanism 80 further comprises a connecting member 82. The connecting member 82 is located on the side of the first weight 50 facing the second weight 81. For example, if the second weight 81 is made of a magnetic material such as iron, the connecting member 82 may be a magnet. However, the connecting member 82 is not limited to the above example and only needs to have a configuration that allows the second weight 81 to rotate in conjunction with the rotation of the first weight 50 when the rotation radius of the first weight 50 is the second rotation radius. For example, the connecting member 82 may be an engaging portion that engages the first weight 50 and the second weight 81 when the rotation radius of the first weight 50 is the second rotation radius. The second weight 81 is supported on the rotation axis 50a of the first weight 50 via a bearing (not shown).

[0068] As described in Embodiment 1, when the displacement of the piston 20 is small, the radius of rotation of the first weight 50 is small. This radius of rotation is the first radius of rotation described above. In this case, as shown in Figure 15, the first weight 50 is not connected to the second weight 81. Therefore, even when the first weight 50 rotates, the second weight 81, which is supported by a bearing on the rotation axis 50a of the first weight 50, does not rotate in conjunction with the rotation of the first weight 50.

[0069] On the other hand, when the displacement of the piston 20 is large, the radius of rotation of the first weight 50 becomes larger than the first radius of rotation. In this case, as shown in Figure 16, the first weight 50 is connected to the second weight 81 by a connecting member 82, and the second weight 81 also rotates in conjunction with the rotation of the first weight 50. The radius of rotation in this case is the second radius of rotation described above.

[0070] As described above, the moment of inertia of the first weight 50 can also be changed in accordance with the displacement of the piston 20 by the moment of inertia variation mechanism 80. Therefore, even when the damper 1 is equipped with the moment of inertia variation mechanism 80 instead of the moment of inertia variation mechanism 60, it can cope with both small and large earthquakes.

[0071] In the examples shown in Figures 15 and 16, the moment of inertia fluctuation mechanism 80 included a second weight 81 and the like in addition to the configuration of the moment of inertia fluctuation mechanism 60, but the configuration of the moment of inertia fluctuation mechanism 80 is not limited to this. For example, the moment of inertia fluctuation mechanism 80 may include a second weight 81 and the like in addition to the configuration of the moment of inertia fluctuation mechanism 70.

[0072] [Embodiment 4] The configuration of the moment of inertia fluctuation mechanism of damper 1 is not limited to those described in the embodiments above. For example, the moment of inertia fluctuation mechanism may include a seismometer for detecting the magnitude of an earthquake and a drive mechanism for moving the first weight 50 along the radial direction of rotational motion according to the magnitude of the earthquake detected by the seismometer. The drive mechanism may be electrically operated, for example. A damper 1 equipped with such a moment of inertia fluctuation mechanism will have the same effects as the damper 1 of the embodiments described above.

[0073] 〔summary〕 This invention can also be expressed as follows:

[0074] A damper according to embodiment 1 of the present invention comprises a cylinder filled with fluid, a piston displaceable relative to the cylinder that divides the inside of the cylinder into a first chamber and a second chamber, a connecting pipe that connects the first chamber and the second chamber and allows the fluid to flow from the first chamber to the second chamber or from the second chamber to the first chamber as the piston is displaced, a rotating body provided in the middle of the connecting pipe and rotating due to the flow of the fluid in the connecting pipe, and a first weight that rotates in conjunction with the rotation of the rotating body, wherein the moment of inertia of the first weight changes according to the operation of the piston.

[0075] In the damper according to embodiment 2 of the present invention, in embodiment 1, the moment of inertia of the first weight changes as the radius of rotation of the first weight changes in accordance with the operation of the piston.

[0076] A damper according to embodiment 3 of the present invention further comprises a tension member extending in a first direction from the first weight in embodiment 2, wherein when the point at which the tension member changes direction from the first direction to the second direction is defined as the direction change point, the distance between one end of the tension member connected to the first weight and the direction change point changes in accordance with the amount of displacement of the piston relative to the cylinder.

[0077] A damper according to embodiment 4 of the present invention further comprises a tension member extending in a first direction from the first weight in embodiment 2, wherein when the point at which the tension member changes direction from the first direction to the second direction is defined as the direction change point, the distance between the other end of the tension member opposite to the end connected to the first weight and the direction change point changes in accordance with the amount of displacement of the piston relative to the cylinder.

[0078] A damper according to embodiment 5 of the present invention further comprises, in any of embodiments 2 to 4, a guide portion having a plurality of regions, and a guided portion fixed to the cylinder and movable along the guide portion.

[0079] A damper according to embodiment 6 of the present invention further comprises a biasing member that biases the first weight in a direction that reduces the rotational radius of the first weight, as in embodiment 2.

[0080] A damper according to embodiment 7 of the present invention further comprises a tension member extending in a first direction from the first weight in embodiment 6, and when the point at which the tension member changes direction from the first direction to the second direction is defined as the direction change point, the biasing member biases the tension member such that it increases the distance between the other end of the tension member opposite to the end connected to the first weight and the direction change point.

[0081] A damper according to embodiment 8 of the present invention further comprises, in embodiment 2, a tension member that applies a force to the first weight in a direction that reduces the rotational radius of the first weight, and a stopper that defines the minimum value of the rotational radius.

[0082] A damper according to embodiment 9 of the present invention further comprises, in any embodiment 2 to 8, a second weight which does not rotate when the turning radius is a first turning radius, and rotates in conjunction with the rotation of the first weight when the turning radius is a second turning radius which is larger than the first turning radius.

[0083] In the damper according to embodiment 10 of the present invention, in any of embodiments 1 to 9, the axis of rotation of the rotational motion of the first weight is parallel to the vertical direction.

[0084] A building according to embodiment 11 of the present invention comprises a damper according to any of embodiments 1 to 10, a first structure, a second structure, and an elastic body connected in series with the damper between the first structure and the second structure.

[0085] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of Symbols]

[0086] 1 Damper 10 cylinders 11 Room 1 12 Room 2 20 pistons 30 Communication pipe 40 Rotating Bodies 50 1st spindle 60, 60A, 70, 80 Moment of Inertia Fluctuation Mechanism 75. Biasing member 81 Second weight 100 Buildings 110 1st structure 120 Second structure 150 Elastic body

Claims

1. A cylinder filled with fluid, A piston that is displaceable relative to the cylinder divides the inside of the cylinder into a first chamber and a second chamber, A connecting pipe that connects the first chamber and the second chamber, and which allows the fluid to flow from the first chamber to the second chamber or from the second chamber to the first chamber as the piston is displaced, A rotating body is provided in the middle of the aforementioned connecting pipe and rotates due to the flow of the fluid in the connecting pipe, A first weight that rotates in conjunction with the rotation of the aforementioned rotating body, Equipped with, As the rotation radius of the first weight changes in accordance with the movement of the piston, the moment of inertia of the first weight changes. The device further comprises a tension member extending in a first direction from the first weight, When the point at which the tension member changes direction from the first direction to the second direction is defined as the direction change point, A damper in which the distance between one end of the tension member connected to the first weight and the direction change point changes according to the amount of displacement of the piston relative to the cylinder.

2. A cylinder filled with fluid, A piston that is displaceable relative to the cylinder divides the inside of the cylinder into a first chamber and a second chamber, A connecting pipe that connects the first chamber and the second chamber, and which allows the fluid to flow from the first chamber to the second chamber or from the second chamber to the first chamber as the piston is displaced, A rotating body is provided in the middle of the aforementioned connecting pipe and rotates due to the flow of the fluid in the connecting pipe, A first weight that rotates in conjunction with the rotation of the aforementioned rotating body, Equipped with, As the rotation radius of the first weight changes in accordance with the movement of the piston, the moment of inertia of the first weight changes. The device further comprises a tension member extending in a first direction from the first weight, When the point at which the tension member changes direction from the first direction to the second direction is defined as the direction change point, A damper in which the distance between the other end of the tension member, opposite to the end connected to the first weight, and the direction change point changes in accordance with the amount of displacement of the piston relative to the cylinder.

3. A cylinder filled with fluid, A piston that is displaceable relative to the cylinder divides the inside of the cylinder into a first chamber and a second chamber, A connecting pipe that connects the first chamber and the second chamber, and which allows the fluid to flow from the first chamber to the second chamber or from the second chamber to the first chamber as the piston is displaced, A rotating body is provided in the middle of the aforementioned connecting pipe and rotates due to the flow of the fluid in the connecting pipe, A first weight that rotates in conjunction with the rotation of the aforementioned rotating body, Equipped with, As the rotation radius of the first weight changes in accordance with the movement of the piston, the moment of inertia of the first weight changes. A guide section having multiple areas, A guided portion fixed to the cylinder and movable along the guide portion, A damper, which is an additional feature.

4. A cylinder filled with fluid, A piston that is displaceable relative to the cylinder divides the inside of the cylinder into a first chamber and a second chamber, A connecting pipe that connects the first chamber and the second chamber, and which allows the fluid to flow from the first chamber to the second chamber or from the second chamber to the first chamber as the piston is displaced, A rotating body is provided in the middle of the aforementioned connecting pipe and rotates due to the flow of the fluid in the connecting pipe, A first weight that rotates in conjunction with the rotation of the aforementioned rotating body, Equipped with, As the rotation radius of the first weight changes in accordance with the movement of the piston, the moment of inertia of the first weight changes. The device further comprises a biasing member that biases the first weight in a direction that reduces the radius of rotation of the first weight, The device further comprises a tension member extending in a first direction from the first weight, When the point at which the tension member changes direction from the first direction to the second direction is defined as the direction change point, The biasing member is a damper that biases the tensioning member such that it increases the distance between the other end of the tensioning member opposite to the end connected to the first weight and the point of change of direction.

5. A cylinder filled with fluid, A piston that is displaceable relative to the cylinder divides the inside of the cylinder into a first chamber and a second chamber, A connecting pipe that connects the first chamber and the second chamber, and which allows the fluid to flow from the first chamber to the second chamber or from the second chamber to the first chamber as the piston is displaced, A rotating body is provided in the middle of the aforementioned connecting pipe and rotates due to the flow of the fluid in the connecting pipe, A first weight that rotates in conjunction with the rotation of the aforementioned rotating body, Equipped with, As the rotation radius of the first weight changes in accordance with the movement of the piston, the moment of inertia of the first weight changes. A tension member that applies a force to the first weight in a direction that reduces the rotational radius of the first weight, A damper further comprising a stopper that defines the minimum value of the turning radius.

6. A cylinder filled with fluid, A piston that is displaceable relative to the cylinder divides the inside of the cylinder into a first chamber and a second chamber, A connecting pipe that connects the first chamber and the second chamber, and which allows the fluid to flow from the first chamber to the second chamber or from the second chamber to the first chamber as the piston is displaced, A rotating body is provided in the middle of the aforementioned connecting pipe and rotates due to the flow of the fluid in the connecting pipe, A first weight that rotates in conjunction with the rotation of the aforementioned rotating body, Equipped with, As the rotation radius of the first weight changes in accordance with the movement of the piston, the moment of inertia of the first weight changes. A damper further comprising a second weight that does not rotate when the rotation radius is a first rotation radius, and rotates in conjunction with the rotation of the first weight when the rotation radius is a second rotation radius that is larger than the first rotation radius.

7. The damper according to claim 1, wherein the axis of rotation of the rotational motion of the first weight is parallel to the vertical direction.

8. A damper according to any one of claims 1 to 7, The first structure and The second structure and A building comprising an elastic body connected in series with the damper between the first structure and the second structure.

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