Rotating Inertia Mass Damper

Abstract

To provide a rotational inertia mass damper which has a pressure motor, and can be compactly used as a seismic isolator by shortening a length in an axial line direction.SOLUTION: A mass damper 1 comprises: an inner cylinder 2 which is filled with a working fluid HF; an outer cylinder 9 for defining a tank chamber 12 between the inner cylinder 2 and itself; a piston 3 slidably arranged in the inner cylinder 2, and partitioning a first oil chamber 2e at a first end wall 2b side and a second oil chamber 2f at a second end wall 2c side; a piston rod 10 extending to the first oil chamber 2e side from the piston 3; a communication path 4 communicating with the first and second oil chambers 2e, 2f, and penetrating the outer cylinder 9; first and second check valves 27, 25 for allowing only a flow of the working fluid HF from the tank chamber 12 to the second oil chamber 2f, and a flow in a reverse direction; a gear motor 5 for converting the circulation of the working fluid HF in the communication path 4 to a rotational motion; and a flywheel 6 driven by the gear motor 5, and exerting a rotational inertia mass effect.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a rotary inertia mass damper that suppresses vibrations of a structure by utilizing the rotary inertia mass effect of a rotating mass driven by a pressure motor. [Background technology]

[0002] The applicant has disclosed this type of rotary inertia mass damper in, for example, Patent Document 1. This rotary inertia mass damper is installed as a vibration control device, for example, between an upper beam and a lower beam in a structure, and includes a cylinder filled with working fluid and connected to the upper beam, a piston slidably provided within the cylinder and dividing the interior of the cylinder into a first fluid chamber and a second fluid chamber, a piston rod extending axially from the piston to both sides, penetrating both end walls of the cylinder and connected at one end to the lower beam, and a communication passage bypassing the piston and communicating with the first and second fluid chambers. A gear motor is provided in the communication passage, and a rotating mass is connected to the gear motor.

[0003] In this rotary inertia mass damper, when the upper and lower beams of a structure are displaced relative to each other during an earthquake or other event, the relative displacement is transmitted to the cylinder and piston, causing the piston to reciprocate relative to the cylinder. As a result, the working fluid in one of the first and second fluid chambers is pushed out by the piston, flows through the connecting passage, and enters the gear motor. The gear motor converts the flow of the working fluid into rotational motion, which is transmitted to the rotating mass, thereby producing a rotational inertia mass effect. Furthermore, the viscous resistance of the working fluid as it flows through the connecting passage also produces a viscous damping effect, resulting in a vibration-damping effect. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-94680 Summary of the Invention [Problem to be solved by the invention]

[0005] When a gear motor-type rotary inertia mass damper such as the one described above is installed between a structure and the ground and used as a seismic isolation device, the stroke (relative displacement) of the damper is generally much larger than when it is used as a vibration control device inside the structure.In contrast, with the conventional rotary inertia mass damper described above, the piston rod extends on both sides of the piston, and the axial installation length of the damper must be at least the sum of the length of the piston rod and the stroke of the damper, which creates the problem that the damper cannot be configured compactly in the axial direction.

[0006] The present invention has been made to solve these problems, and aims to provide a rotary inertia mass damper that can be used compactly as a seismic isolation device by shortening the axial length when equipped with a pressure motor. [Means for solving the problem]

[0007] To achieve this object, the invention of claim 1 provides a rotary inertia mass damper that is provided between a first portion and a second portion that are displaced relative to each other in a system including a structure and that suppresses vibration of the structure, the rotary inertia mass damper comprising: an inner cylinder having a peripheral wall and first and second end walls that face each other in the axial direction and that is filled with a working fluid; an outer cylinder that is provided so as to surround at least the peripheral wall and the second end wall of the inner cylinder and defines a tank chamber for storing the working fluid between the peripheral wall and the second end wall and is connected to the first portion; a piston that is provided slidably within the inner cylinder and that divides the interior of the inner cylinder into a first fluid chamber on the first end wall side and a second fluid chamber on the second end wall side; and a piston that is provided integrally with the piston. a piston rod extending axially from the piston toward the first fluid chamber, penetrating the first end wall to the outside, and connected to the second portion; a communication passage bypassing the piston, communicating with the first and second fluid chambers, penetrating the outer cylinder to the outside, and filled with working fluid; a first check valve provided in the second end wall of the inner cylinder and allowing only the flow of working fluid from the tank chamber to the second fluid chamber, and a second check valve provided in the communication passage and allowing only the flow of working fluid from the second fluid chamber to the tank chamber; a pressure motor provided in the communication passage and converting the flow of working fluid in the communication passage into rotational motion; and a rotary mass connected to the pressure motor and driven by the pressure motor to exhibit a rotary inertia mass effect. a first pressure regulating valve provided on the piston, the first pressure regulating valve opening when the pressure of the working fluid in the first fluid chamber reaches a first predetermined pressure and causing the working fluid in the first fluid chamber to flow out to the second fluid chamber, thereby adjusting the pressure in the first fluid chamber, in order to mitigate impact to the pressure motor; a second pressure regulating valve opening when the pressure of the working fluid in the second fluid chamber reaches the first predetermined pressure and causing the working fluid in the second fluid chamber to flow out to the first fluid chamber, in order to mitigate impact to the pressure motor; a first relief valve provided on the piston, the first pressure regulating valve opening when the pressure of the working fluid in the first fluid chamber reaches a second predetermined pressure higher than the first predetermined pressure and causing the pressure in the first fluid chamber to be released to the second fluid chamber; and a second relief valve opening when the pressure of the working fluid in the second fluid chamber reaches the second predetermined pressure and causing the pressure in the second fluid chamber to be released to the first fluid chamber; and a drain pipe having one end connected to a drain passage in a housing of the pressure motor and the other end inserted into the tank chamber. The present invention is characterized by comprising:

[0008] The rotary inertia mass damper of the present invention is a pressure motor type having the inner cylinder, outer cylinder, piston, piston rod, connecting passage, pressure motor, and rotary mass configured as described above, and is installed between a first part and a second part that are relatively displaceable in a system including a structure whose vibration is to be suppressed. In particular, in this rotary inertia mass damper, the piston rod extends only toward the first fluid chamber, a working fluid is stored in a tank chamber between the inner cylinder and the outer cylinder, and first and second check valves are provided on a second end wall on the side of the second fluid chamber where the piston rod is not provided, which allow the working fluid to flow only from the tank chamber to the second fluid chamber and only to flow in the reverse direction, respectively.

[0009] In this configuration, when vibrations are input to the structure during an earthquake or other event, causing relative displacement between the first and second parts, the relative displacement is transmitted to the outer cylinder and the piston rod, causing the piston to slide (reciprocate) within the inner cylinder. As the piston reciprocates, the working fluid in the first or second fluid chamber on either side is pushed out by the piston and flows into a communication passage in which a pressure motor is installed. As a result, the flow of the working fluid is converted into rotational motion by the pressure motor and transmitted to the rotating mass, thereby producing a rotational inertia mass effect by the rotating mass, thereby suppressing vibration of the structure.

[0010] Furthermore, in the rotary inertia mass damper of the present invention, when the piston moves toward the first fluid chamber (when the piston rod extends), the pressure in the second fluid chamber decreases, causing the first check valve to open, and working fluid flows from the tank chamber into the second fluid chamber, thereby replenishing the second fluid chamber with working fluid that is insufficient due to the difference in cross-sectional area between the first and second fluid chambers depending on whether the piston rod is present or not.

[0011] Conversely, when the piston moves toward the second fluid chamber (when the piston rod retracts), the pressure in the second fluid chamber increases, causing the second check valve to open, allowing the working fluid to flow from the second fluid chamber to the tank chamber. As a result, excess working fluid due to the difference in cross-sectional area between the first and second fluid chambers depending on whether the piston rod is present or not is discharged from the second fluid chamber.

[0012] As described above, when the structure vibrates, as the piston reciprocates, the first and second check valves automatically replenish or discharge the working fluid to the second fluid chamber just enough depending on whether the piston rod is present or not. This ensures smooth reciprocation of the piston and smooth flow of the working fluid in the communication passage, ensuring good operation of the pressure motor and allowing the rotary inertia mass effect of the rotating mass to be exerted well.

[0013] Furthermore, according to the rotary inertia mass damper of the present invention, the piston rod is provided on only one side of the piston, and is shorter than the conventional case in which the piston rod is provided on both sides of the piston. This allows the axial length of the rotary inertia mass damper to be shortened accordingly, and the damper can be used compactly as a seismic isolation device.

[0015] Also, According to this configuration, the first pressure regulating valve and the second pressure regulating valve are provided on the piston. 。 The first pressure regulating valve opens when the pressure of the working fluid in the first fluid chamber reaches a first predetermined pressure, and regulates the pressure in the first fluid chamber by causing the working fluid in the first fluid chamber to flow into the second fluid chamber. This suppresses an increase in pressure in the first fluid chamber, and provides a damping force due to viscous resistance when the working fluid flows through the first pressure regulating valve. This reduces the impact on the pressure motor provided in the communication passage. Similarly, when the pressure of the working fluid in the second fluid chamber reaches the first predetermined pressure, the valve opens and the working fluid in the second fluid chamber flows out into the first fluid chamber, thereby adjusting the pressure in the second fluid chamber. This suppresses an increase in pressure in the second fluid chamber, and also provides a damping force due to the viscous resistance when the working fluid flows through the second pressure regulating valve. This reduces the impact on the pressure motor provided in the communication passage. do.

[0016] Due to the above-described action of the first and second pressure regulating valves, the first and second fluid chambers function as cushions in the early stages of vibration, thereby mitigating the impact on the pressure motor and avoiding the adverse effects of the impact.

[0018] moreover, According to this configuration, the first relief valve and the second relief valve are provided on the piston. 。The first relief valve opens when the pressure of the working fluid in the first fluid chamber reaches a second predetermined pressure that is higher than the first predetermined pressure, thereby allowing the working fluid to escape to the second fluid chamber, and if the damping coefficient after relief is 0, the pressure in the first fluid chamber is limited to be equal to or lower than the second predetermined pressure. Similarly, the second relief valve opens when the pressure of the working fluid in the second fluid chamber reaches the second predetermined pressure, thereby allowing the working fluid to escape to the first fluid chamber, and if the damping coefficient after relief is 0, the pressure in the second fluid chamber is limited to be equal to or lower than the second predetermined pressure. As a result, excessive pressure in the first and second fluid chambers can be prevented, and the axial force acting on the inner cylinder and the piston and the pressure of the working fluid acting on the pressure motor can be appropriately limited. One end of the drain pipe is connected to the drain passage of the housing of the pressure motor, and the other end is inserted into the tank chamber. With this configuration, if the pressure of the working fluid in the housing increases and the working fluid leaks from the drain passage of the pressure motor, the working fluid is released into the tank chamber, which is at atmospheric pressure, via the drain pipe. This reliably prevents excessive pressure buildup inside the housing of the pressure motor.

[0019] Claim 2 The invention according to claim 1 to In the described rotary inertia mass damper, the communication passage penetrates the outer cylinder in a liquid-tight manner via a seal and extends to the outside.

[0020] With this configuration, the gap between the communicating passage and the outer cylinder through which the communicating passage passes is kept liquid-tight by the seal, thereby reliably preventing leakage of the working fluid inside the tank chamber from this gap when the rotary inertia mass damper is installed, operated, or transported. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a cross-sectional view showing a mass damper according to an embodiment of the present invention. [Figure 2] FIG. 1 is a diagram illustrating an example in which a seismic isolation device including a mass damper is installed in a structure. [Figure 3] FIG. 1 is a diagram showing a model of an additional vibration system configured by a mass damper and a support member. [Figure 4] FIG. 10 is a diagram showing the relationship between the speed of hydraulic oil flowing inside the piston and the damping force. DETAILED DESCRIPTION OF THE INVENTION

[0022] A preferred embodiment of the present invention will be described in detail below with reference to the drawings. As shown in Fig. 1, a rotary inertia mass damper (hereinafter referred to as "mass damper") 1 according to this embodiment includes an inner cylinder 2 arranged horizontally, an outer cylinder 9 provided outside the inner cylinder 2, a piston 3 provided within the inner cylinder 2, a communication passage 4 that bypasses the piston 3 and communicates with the inside of the inner cylinder 2, a gear motor 5 serving as a pressure motor and arranged in the communication passage 4, and a flywheel 6 connected to the gear motor 5.

[0023] The inner cylinder 2 has a cylindrical peripheral wall 2a, a thin plate-like first end wall 2b provided at both ends of the peripheral wall 2a, and a thicker block-like second end wall 2c, which are integral with the peripheral wall 2a. The internal space of the inner cylinder 2 is defined by these three walls 2a to 2c.

[0024] The piston 3 is axially slidably disposed within the inner cylinder 2, dividing the interior space of the inner cylinder 2 into a first oil chamber 2e on the first end wall 2b side and a second oil chamber 2f on the second end wall 2c side. The first and second oil chambers 2e, 2f and the communication passage 4 are filled with hydraulic oil HF. The hydraulic oil HF is a normal hydraulic oil with appropriate viscosity.

[0025] A piston rod 10 is provided concentrically and integrally with the piston 3. The piston rod 10 is provided only on the first oil chamber 2e side, and extends liquid-tightly through a first end wall 2b of the inner cylinder 2 and a first end wall 9b (described later) of the outer cylinder 9 via a seal 11, to the outside. A first mounting fixture FL1 is attached to the outer end of the piston rod 10 via a universal joint (not shown).

[0026] The outer cylinder 9 surrounds the entire inner cylinder 2 and integrally includes a cylindrical peripheral wall 9a and plate-like first and second end walls 9b, 9c provided at both ends thereof, with the first end wall 9b being fixed in contact with the first end wall 2b of the inner cylinder 2. A space is defined between the peripheral walls 2a, 9a and between the second end walls 2c, 9c of the inner cylinder 2 and the outer cylinder 9, and this space serves as a tank chamber 12. Hydraulic oil HF is stored in the tank chamber 12, with an air layer A remaining at the top. A second mounting fixture FL2 is attached to the second end wall 9c of the outer cylinder 9 via a universal joint (not shown).

[0027] The communication passage 4 is gate-shaped and is composed of a pair of vertical passage sections 4a, 4a extending in the up-down direction and a horizontal passage section 4b connected between the upper ends of the vertical passage sections 4a, 4a. The vertical passage sections 4a, 4a communicate at their lower ends with the first and second oil chambers 2e, 2f of the inner cylinder 2, respectively, and also liquid-tightly penetrate the peripheral wall 2a of the inner cylinder 2 via a seal 13, and liquid-tightly penetrate the peripheral wall 9a of the outer cylinder 9 via a seal 14.

[0028] The gear motor 5 is provided in the horizontal passage portion 4b of the communication passage 4. The gear motor 5 is, for example, an internal gear motor, and has a housing 7 that communicates with the horizontal passage portion 4b through two inlets and outlets (not shown), a rotatable input gear and an output gear (neither shown) that are housed in the housing 7 and mesh with each other, and an output shaft 8 that is integral with the output gear. Note that the gear motor 5 may be an external gear motor instead of an internal gear motor.

[0029] A drain passage (not shown) for discharging the hydraulic oil HF is provided within the housing 7. One end of a drain pipe 31 is connected to this drain passage, and the other end of the drain pipe 31 is inserted into the tank chamber 12.

[0030] The flywheel 6 is attached to the output shaft 8 of the gear motor 5. The flywheel 6 is formed into a disk shape from a material with a relatively high specific gravity, such as steel, and is provided coaxially and integrally with the output shaft 8.

[0031] Meanwhile, four communication passages that penetrate the piston 3 in the axial direction and communicate with the first and second oil chambers 2e, 2f are formed in the piston 3. Each of these communication passages is provided with a first pressure regulating valve 21, a first relief valve 22, a second pressure regulating valve 23, and a second relief valve 24. Each of these valves 21 to 24 is configured as a normally closed valve, and includes a valve body that opens and closes the communication passage, and a spring that biases the valve body toward the valve closing side.

[0032] The first pressure regulating valve 21 opens when the pressure in the first oil chamber 2e reaches a first predetermined pressure close to zero, and regulates the pressure in the first oil chamber 2e by allowing hydraulic oil HF to flow to the second oil chamber 2f. The first relief valve 22 opens when the pressure in the first oil chamber 2e reaches a second predetermined pressure (corresponding to a relief load) higher than the first predetermined pressure, and allows hydraulic oil HF to escape to the second oil chamber 2f. When the damping coefficient after relief is zero, the first pressure regulating valve 23 limits the pressure in the second oil chamber 2f to equal to or less than the second predetermined pressure by opening when the pressure in the second oil chamber 2f reaches the first predetermined pressure. The second relief valve 24 opens when the pressure in the second oil chamber 2f reaches the second predetermined pressure, and when the damping coefficient after relief is zero, the second pressure regulating valve 23 limits the pressure in the second oil chamber 2f to equal to or less than the second predetermined pressure.

[0033] Furthermore, two communication passages are formed in the second end wall 2c of the inner cylinder 2, penetrating in the axial direction and communicating with the second oil chamber 2f and the tank chamber 12. A third pressure regulating valve 25 and a third relief valve 26, which are configured similarly to the above-described valves 21 to 24, are provided in these communication passages, respectively.

[0034] The third pressure regulating valve 25 functions as a second check valve that only allows the hydraulic oil HF to flow from the second oil chamber 2f side to the tank chamber 12 side, and opens when the pressure in the second oil chamber 2f reaches a first predetermined pressure, thereby adjusting the pressure in the second oil chamber 2f by allowing the hydraulic oil HF to flow toward the tank chamber 12. The third relief valve 26 opens when the pressure in the second oil chamber 2f reaches a second predetermined pressure, allowing the hydraulic oil HF to escape toward the tank chamber 12, thereby limiting the pressure in the second oil chamber 2f to below the second predetermined pressure if the damping coefficient after relief is 0.

[0035] Furthermore, two communication holes penetrating in the axial direction are formed in the second end wall 2c of the inner cylinder 2, and these communication holes are opened and closed by a check valve 27. The check valve 27 is composed of valve bodies 27a, 27a that open and close the communication holes, and a spring 27b that biases the valve body 27a to the valve closing side, thereby allowing the hydraulic oil HF to flow only from the tank chamber 12 side to the second oil chamber 2f side.

[0036] As shown in FIG. 2, the mass damper 1 configured as described above is installed as a seismic isolation device 51, together with a plurality of seismic isolation bearings 52, such as laminated rubber bearings, between a structure (building) B and its foundation F. Specifically, the mass damper 1 is attached to a first support member EN1 hanging down from the structure B and a second support member EN2 erected upright from the foundation F, via first and second mounting fixtures FL1 and FL2, respectively. The operation of the mass damper 1 configured and installed in this manner will now be described.

[0037] First, when the structure B is not vibrating, the mass damper 1 is in the initial state shown in Figure 1. When the foundation F vibrates from this initial state during an earthquake, a relative displacement occurs between the first and second support members EN1 and EN2. This relative displacement is transmitted to the inner cylinder 2 and the piston 3, causing the piston 3 to reciprocate within the inner cylinder 2.

[0038] For example, when the piston 3 moves toward the first oil chamber 2e (when the piston rod 10 is extended), the pressure in the first oil chamber 2e increases due to the pressure from the piston 3. When the pressure reaches a first predetermined pressure, the first pressure regulating valve 21 opens, and a portion of the hydraulic oil HF pressed by the piston 3 flows through the first pressure regulating valve 21 to the second oil chamber 2f. The remainder of the hydraulic oil HF flows from the first oil chamber 2e into the horizontal passage portion 4b via one vertical passage portion 4a of the communication passage 4, flows through the housing 7 of the gear motor 5, and then returns to the second oil chamber 2f via the other vertical passage portion 4a. In this case, the hydraulic oil HF that is insufficient in the second oil chamber 2f due to the difference in cross-sectional area between the first and second oil chambers 2e, 2f depending on whether the piston rod 10 is present or not is replenished from the tank chamber 12 to the second oil chamber 2f by the check valve 27 opening.

[0039] On the other hand, conversely to the above, when the piston 3 moves toward the second oil chamber 2f (when the piston rod 10 contracts), the pressure in the second oil chamber 2f increases due to the pressure from the piston 3. When the pressure reaches a first predetermined pressure, the second pressure regulating valve 23 opens, and a portion of the hydraulic oil HF pressed by the piston 3 flows into the first oil chamber 2e. Also, a portion of the pressed hydraulic oil HF flows from the second oil chamber 2f through one vertical passage portion 4a of the communication passage 4 into the horizontal passage portion 4b, flows through the housing 7 of the gear motor 5, and then returns to the first oil chamber 2e through the other vertical passage portion 4a. In this case, the excess hydraulic oil HF in the second oil chamber 2f due to the difference in cross-sectional area between the first and second oil chambers 2e, 2f, is discharged from the second oil chamber 2f to the tank chamber 12 by opening the third pressure regulating valve 25.

[0040] As described above, when the hydraulic oil HF flows inside the housing 7 of the gear motor 5, the pressure of the hydraulic oil HF is converted into the rotational motion of the gear motor 5, and the flywheel 6 integrated with the output shaft 8 is rotated, thereby exerting a rotational inertia mass effect (inertia force). In addition, when the hydraulic oil HF flows through the communication passage 4, a viscous damping effect (viscous force) is exerted due to the viscous resistance, and this, together with the rotational inertia mass effect, can provide a vibration suppression effect for the structure.

[0041] Furthermore, during operation of the mass damper 1, when the pressure of the hydraulic oil HF in the first oil chamber 2e reaches a first predetermined pressure, the first pressure regulating valve 21 opens and causes the hydraulic oil HF to flow into the second oil chamber 2f, thereby releasing the pressure in the first oil chamber 2e and suppressing its increase, and a damping force is generated by viscous resistance when the hydraulic oil HF flows through the first pressure regulating valve 21. Similarly, when the pressure of the hydraulic oil HF in the second oil chamber 2f reaches the first predetermined pressure, the second pressure regulating valve 23 opens and causes the hydraulic oil HF to flow into the first oil chamber 2e, thereby releasing the pressure in the second oil chamber 2f and suppressing its increase, and a damping force is generated by viscous resistance when the hydraulic oil HF flows through the second pressure regulating valve 23. Due to the action of the first and second pressure regulating valves 21, 23 as described above, the first and second oil chambers 2e, 2f function as cushions at the beginning of vibration, thereby mitigating the impact on the gear motor 5 and avoiding the adverse effects of the impact.

[0042] Furthermore, when the pressure of the hydraulic oil HF in the first oil chamber 2e reaches a second predetermined pressure, the first relief valve 22 opens, and the hydraulic oil HF is released to the second oil chamber 2f. As a result, if the damping coefficient after relief is 0, the pressure in the first oil chamber 2e is limited to be equal to or lower than the second predetermined pressure. Similarly, when the pressure of the hydraulic oil HF in the second oil chamber 2f reaches the second predetermined pressure, the second relief valve 24 opens, and the hydraulic oil HF is released to the first oil chamber 2e. As a result, if the damping coefficient after relief is 0, the pressure in the second oil chamber 2f is limited to be equal to or lower than the second predetermined pressure. As a result, the pressures in the first and second oil chambers 2e and 2f are prevented from becoming excessive, and the axial force acting on the inner cylinder 2 and the piston 3 and the pressure of the hydraulic oil HF acting on the gear motor 5 are appropriately limited.

[0043] Furthermore, for example, when the gear motor 5 operates for a long period due to the response of the structure to the input of long-period seismic motion, the pressure of the hydraulic oil HF in the housing 7 increases and, in this case, the hydraulic oil HF leaks from the drain of the gear motor 5. In this case, the hydraulic oil HF is released to the tank chamber 12, which is in atmospheric conditions, via the drain pipe 31. This reliably prevents excessive pressure buildup inside the housing 7.

[0044] The additional vibration system consisting of the mass damper 1 and support members (first and second support members EN1, EN2) described above is modeled as shown in Figure 3. That is, the model is made up of (a) an inertial mass element with equivalent mass λmd consisting of the flywheel 6 and hydraulic oil HF, and (b) a viscous element with damping coefficient cd consisting of the hydraulic oil HF flowing through the communication passage 4 and gear motor 5, which are in a parallel relationship with each other, (c) a viscous element with damping coefficient c1 consisting of the hydraulic oil HF flowing through the pressure regulating valves (first and second pressure regulating valves 21, 23) before relief by the relief valves (first and second relief valves 22, 24), a limiting element for the relief load Fr by the relief valves, and a viscous element with damping coefficient c2 consisting of the hydraulic oil HF flowing through the pressure regulating valves and relief valves after relief, and (d) a spring element with stiffness kb consisting of a support member including the compression stiffness of the hydraulic oil HF, all of which are connected in series.

[0045] In the model of Figure 3, Fd is the damper external force acting on the mass damper 1, and Fr is the relief load of the first and second relief valves 22, 24. xb is the displacement of the support member including the amount of compression of the hydraulic oil HF. xiHGD is the piston movement amount when the damper external force Fd acts, and is expressed by the following equation (1) where V is the displacement flow rate associated with the movement of the piston 3 and Ap is the piston cross-sectional area. xiHGD = V / Ap (1) Furthermore, xr is the apparent movement amount obtained by dividing the flow rate Vr of the hydraulic oil HF flowing through the pressure regulating valve and the relief valve into the piston 3 by the piston cross-sectional area Ap, and is expressed by the following equation (2): xd is the apparent movement amount obtained by dividing the flow rate Vd of the hydraulic oil HF flowing through the communicating passage 4 to the gear motor 5 by the piston cross-sectional area Ap, and is expressed by the following equation (3): xr = Vr / Ap (2) xd = Vd / Ap (3)

[0046] Then, the relationship of the following formula (4) is established among V, Vr, and Vd, and therefore the relationship of the following formula (5) is established from formula (4) and formulas (1) to (3). V = Vr + Vd (4) xiHGD = xr+xd (5) Furthermore, the pressure acting on the pressure regulating valve and relief valve installed on the piston 3 is equal to the pressure acting on the gear motor 5. (6)

[0047] From the relationships in (5) and (6), the following equations (7) to (9) hold. x = xb+xiHGD = xb+xr+xd ···(7) When |vr|≦Fr / c1 (condition before relief) Fd = kb xb = c1·vr = λmd·αd+cd·vd ···(8) When |vr|>Fr / c1 (condition after relief) Fd = kb xb = sgn(vr)·Fr+c2·(vr-sgn(vr)·Fr / c1) = λmd·αd+cd·vd ···(9) where x: displacement of the entire additional vibration system c1: damping coefficient before relief c2: Damping coefficient after relief vr:xr speed vd:xd speed αd:Acceleration of xd λmd: equivalent mass of the mass damper cd: damping coefficient of the mass damper

[0048] From the above equations (8) and (9), the relationship between the apparent velocity vr calculated from the hydraulic oil HF flowing inside the piston 3 through the pressure regulating valve and the relief valve and the damping force F (= damper reaction force) due to its viscous resistance is expressed as shown in Figure 4 for the range of vr ≥ 0. In other words, the damping force F exhibits bilinear characteristics with respect to the velocity vr, and the damping coefficient becomes a larger damping coefficient c1 until the relief load Fr is reached because the hydraulic oil HF flows only through the pressure regulating valve, and after the relief load Fr is reached, the damping coefficient becomes a smaller damping coefficient c2 because the hydraulic oil HF flows through both the pressure regulating valve and the relief valve.

[0049] As described above, according to the mass damper 1 of this embodiment, the piston rod 10 is provided only on one side of the piston 3 and is shorter than the conventional case in which the piston rod 10 is provided on both sides of the piston. This allows the axial length of the mass damper 1 to be shortened accordingly, allowing it to be used compactly as a seismic isolation device.

[0050] Furthermore, when the structure B vibrates, as the piston 3 reciprocates, the check valve 27 and the third pressure regulating valve 25 automatically replenish or discharge just the right amount of hydraulic oil HF to the second oil chamber 2f depending on the presence or absence of the piston rod 10. This ensures smooth reciprocation of the piston 3 and smooth flow of hydraulic oil HF in the communication passage 4, ensuring good operation of the gear motor 5 and allowing the rotary inertia mass effect of the rotating mass to be exerted well.

[0051] Furthermore, when the pressure of the hydraulic oil HF in the first oil chamber 2e or the second oil chamber 2f reaches a first predetermined pressure, the first or second pressure regulating valve 21, 23 provided on the piston 3 opens, causing the hydraulic oil HF to flow into the opposite second oil chamber 2f or the first oil chamber 2e. This suppresses the increase in pressure in the first oil chamber 2e or the second oil chamber 2f, and provides a damping force due to the viscous resistance of the hydraulic oil HF as it flows through the first or second pressure regulating valve 21, 23. Due to the above-mentioned action, the first and second oil chambers 2e, 2f function as cushions at the beginning of vibration, thereby mitigating the impact on the gear motor 5 and preventing any adverse effects of the impact.

[0052] Furthermore, when the pressure of the hydraulic oil HF in the first oil chamber 2e or the second oil chamber 2f reaches a second predetermined pressure that is higher than the first predetermined pressure, the first or second relief valve 22, 24 provided on the piston 3 opens to release the hydraulic oil HF to the opposite second oil chamber 2f or the first oil chamber 2e. As a result, if the damping coefficient c2 is 0 after the relief load Fr is reached, the pressure of the hydraulic oil HF in the first oil chamber 2e or the second oil chamber 2f is limited to be equal to or lower than the second predetermined pressure, thereby preventing it from becoming excessive, and making it possible to appropriately limit the axial force acting on the inner cylinder 2 and the piston 3 and the pressure of the hydraulic oil HF acting on the gear motor 5.

[0053] Furthermore, a seal 14 is provided in the gap between the vertical passage portions 4a, 4a of the communicating passage 4 and the outer cylinder 9 through which they pass, and this gap is kept liquid-tight, so that leakage of the hydraulic oil HF in the tank chamber 12 from this gap can be reliably prevented when the mass damper 1 is installed, operated, or transported.

[0054] The present invention is not limited to the embodiment described above and can be embodied in various forms. For example, in the embodiment, the third pressure regulating valve 25 and the third relief valve 26, which also serve as the second check valve, are provided on the second end wall 2c of the inner cylinder 2. However, these valves 25 and 26 may be omitted, and only the second check valve that allows the hydraulic oil HF to flow only from the second oil chamber 2f side to the tank chamber 12 side may be provided.

[0055] Furthermore, in the embodiment, the piston 3 is provided with the first and second pressure regulating valves 21, 23 and the first and second relief valves 22, 24, but one or both of these pressure regulating valves and relief valves may be omitted, and a mass damper configured in this manner is also within the scope of the present invention.

[0056] Although a gear motor is used as the pressure motor of the mass damper 1, other types of pressure motors may be used, such as a piston motor, vane motor, or screw motor, as long as they convert the flow of working fluid into rotational motion. Also, in the embodiment, ordinary working oil is used as the working fluid of the damper, but it goes without saying that other appropriate working fluids may also be used.

[0057] In the embodiment, the mass damper 1 is described as being used as a seismic isolation device, but it is not limited to this, and it may also be used as a vibration control device. In addition, the detailed configuration can be appropriately changed within the scope of the spirit of the present invention. [Explanation of symbols]

[0058] 1 Mass damper (rotary inertia mass damper) 2 inner cylinder 2a Circumferential wall of inner cylinder 2b First end wall of inner cylinder 2c Second end wall of inner cylinder 2e 1st oil chamber (1st fluid chamber) 2f 2nd oil chamber (2nd fluid chamber) 3 pistons 4 passages 5 Gear motor (pressure motor) 6 Flywheel (rotating body) 9 Outer cylinder 10 Piston rod 12 Tank Room 14 Seals 21 First pressure regulating valve 22 First relief valve 23 Second pressure regulating valve 24 Second relief valve 25 Third pressure regulating valve (second check valve) 27 Check valve (first check valve) HF hydraulic oil (working fluid) B Structure F Basics

Claims

1. A rotary inertia mass damper is provided between a first portion and a second portion that are displaced relative to each other in a system including a structure, and suppresses vibration of the structure, an inner cylinder having a peripheral wall and first and second end walls opposed to each other in the axial direction, the inner cylinder being filled with a working fluid; an outer cylinder provided to surround at least the peripheral wall and the second end wall of the inner cylinder, defining a tank chamber for storing a working fluid between the peripheral wall and the second end wall, and connected to the first portion; a piston slidably provided within the inner cylinder, the piston dividing the interior of the inner cylinder into a first fluid chamber on the first end wall side and a second fluid chamber on the second end wall side; a piston rod that is integral with the piston, extends from the piston toward the first fluid chamber in the axial direction, penetrates the first end wall, and extends to the outside, and is connected to the second portion; a communication passage that bypasses the piston, communicates with the first and second fluid chambers, penetrates the outer cylinder to extend to the outside, and is filled with working fluid; a first check valve provided on the second end wall of the inner cylinder, the first check valve allowing only a flow of hydraulic fluid from the tank chamber to the second fluid chamber, and a second check valve allowing only a flow of hydraulic fluid from the second fluid chamber to the tank chamber; a pressure motor provided in the communication passage and configured to convert the flow of working fluid in the communication passage into rotational motion; a rotating mass coupled to the pressure motor and driven by the pressure motor to exert a rotary inertia mass effect; a first pressure regulating valve provided on the piston, the first pressure regulating valve opening when the pressure of the working fluid in the first fluid chamber reaches a first predetermined pressure and causing the working fluid in the first fluid chamber to flow out to the second fluid chamber, thereby adjusting the pressure in the first fluid chamber, in order to mitigate impact to the pressure motor; and a second pressure regulating valve opening when the pressure of the working fluid in the second fluid chamber reaches the first predetermined pressure and causing the working fluid in the second fluid chamber to flow out to the first fluid chamber, in order to adjust the pressure in the second fluid chamber, in order to mitigate impact to the pressure motor. a first relief valve provided on the piston, the first relief valve opening when the pressure of the working fluid in the first fluid chamber reaches a second predetermined pressure that is higher than the first predetermined pressure to release the pressure in the first fluid chamber to the second fluid chamber, and a second relief valve opening when the pressure of the working fluid in the second fluid chamber reaches the second predetermined pressure to release the pressure in the second fluid chamber to the first fluid chamber; a drain pipe having one end connected to a drain passage of the housing of the pressure motor and the other end inserted into the tank chamber; A rotary inertia mass damper comprising:

2. A rotary inertia mass damper as described in claim 1, characterized in that the communicating passage penetrates the outer cylinder liquid-tightly via a seal and extends to the outside.

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