Vibration reducing device for gas turbine engine

A vibration reducing device for a gas turbine engine, comprising a rotating shaft that includes a first mass member, a plurality of bearings that rotatably support the rotating shaft, and a stationary body that supports the bearings,

• wherein an annular second mass member having an internal diameter thereof larger than an external diameter of the rotating shaft is rotatably supported in a contact state at a position on the rotating shaft, at which position centrifugal whirling vibration is generated due to imbalance of the first mass member, and
• wherein
• when a mass of the first mass member is defined as m, a mass of the second mass member is defined as M, a shaft amplitude of the rotating shaft is defined as a, a difference between the external diameter of the rotating shaft and the internal diameter of the second mass member is defined as CL, a support spring coefficient of the first mass member is defined as k, a centrifugal whirling angular velocity of the rotating shaft is defined as Ω, and a distance from a center of the rotating shaft to a center of gravity of the first mass member is defined as e,
• when the centrifugal whirling angular velocity Ω of the rotating shaft is less than a centrifugal whirling resonant rotational speed Ω0 of the rotating shaft, in a radial load balance equation
• maΩ2+meΩ2−ka=M(a−CL)Ω2
• the mass M of the second mass member is set so that the shaft amplitude a of the rotating shaft becomes a minimum, and
• when the centrifugal whirling angular velocity Ω of the rotating shaft is larger than the centrifugal whirling resonant rotational speed Ω0 of the rotating shaft, in a radial load balance equation
• maΩ2−meΩ2−ka=M(a−CL)Ω2
• the mass M of the second mass member is set so that the shaft amplitude a of the rotating shaft becomes a minimum.