Rotary inertial mass damper

A rotary inertial mass damper that is interposed between two members which are relatively displaced in a direction in which the members approach or are separated from each other, wherein the members generate a force due to relative acceleration in an approaching or separating direction which is generated between the two members, the damper comprising:

• a cylinder which is connected to one of the two members and in which an operating fluid is sealed;
• a piston rod which is connected to the other of the two members and a part of which is accommodated in the cylinder in a freely reciprocating manner;
• a piston which is provided with the piston rod and partitions the cylinder into two fluid chambers;
• a fluid-pressure motor which has a rotary shaft and is in fluid communication with each of the two fluid chambers via a plurality of connection pipes;
• a rotary weight which is integrally provided on the rotary shaft of the fluid-pressure motor;
• and
• a damping valve biased by a damping spring, the damping valve exhibits a damping force by an operating fluid and applies the damping force in parallel with an inertial mass of the rotary weight,
• wherein the rotary shaft of the fluid-pressure motor rotates due to fluid pressure of an operating fluid that is extruded from one of the fluid chambers through reciprocating movement of the piston rod via connection pipes,
• the fluid-pressure motor is disposed outside the piston and the cylinder, the damping valve is provided in the middle of a pipe system connecting the fluid-pressure motor and the cylinder, and the fluid-pressure motor is configured to exhibit the damping force Fc=c·x, c being a damping coefficient, the damping force being in proportion to the moving speed x of the piston rod,
• and wherein the rotary weight mounted on the rotary shaft of the fluid-pressure motor has an inertial mass Ψ, with a rotary inertial moment of Iθ, the inertial mass determined by the equation,
• ψ
• =
• (
• 2
• ⁢
• π
• x
• 1
• )
• 2
• ×
• I
• 0
• =
• (
• 2
• ⁢
• π
• ⁢
• ⁢
• A
• V
• )
• 2
• ×
• I
• 0
• and wherein a mechanism that generates a burden force FΨ proportional to moving acceleration x of the piston rod is achieved.