Vibration reducing apparatus

1. A vibration reducing apparatus having a vibration damping unit which comprises:

a dynamic mass;

an elastic member configured to apply elastic force to said dynamic mass such that said dynamic mass vibrates in parallel to a vibration damping direction to a vibration damping object;

a control mass;

an actuator coupled to said dynamic mass at a first position of said dynamic mass, to drive said control mass by elongating and contracting in an operation direction of said actuator as a direction of elongation or contraction of said actuator; and

a motion direction converting mechanism configured to couple said control mass to said dynamic mass at a second position of said dynamic mass which is different from the first position and to move said control mass to said dynamic mass into the vibration damping direction through elongation and contraction of said actuator,

wherein said actuator is supported by said dynamic mass such that the operation direction of said actuator is not parallel to the vibration damping direction.

2. The vibration reducing apparatus according to claim 1 , wherein said elastic member and said control mass are arranged such that an elastic member segment as an orthographic projection of said elastic member onto a straight line parallel to the vibration damping direction overlaps with a control mass segment as an orthographic projection of said control mass to the straight line.

3. The vibration reducing apparatus according to claim 1 , wherein said vibration damping unit further comprises a housing which is fixed on the vibration damping object,

wherein said housing comprises:

an upper side member; and

a lower side member disposed to oppose to said upper side member,

wherein said dynamic mass is arranged between said upper side member and said lower side member,

wherein said elastic member comprises:

an upper side elastic member arranged between said upper side member and said dynamic mass; and

a lower side elastic member arranged between said lower side member and said dynamic mass, and

wherein an upper side elastic member junction portion to which said upper side elastic member of said dynamic mass is coupled is arranged to be nearer said lower side member than a lower side elastic member junction portion to which said lower side elastic member of said dynamic mass is coupled.

4. The vibration reducing apparatus according to claim 1 , wherein said vibration damping unit further comprises:

another control mass;

another actuator coupled to said dynamic mass at a third position of said dynamic mass, to drive said another control mass by elongating and contracting in an operation direction of said another actuator; and

another motion direction converting mechanism configured to couple said another control mass to said dynamic mass at a fourth position of said dynamic mass which is different from the first to third positions and to move said control mass to said dynamic mass through elongation and contraction of said another actuator.

5. The vibration reducing apparatus according to claim 1 , wherein said actuator is coupled to said dynamic mass through said motion direction converting mechanism.

6. A helicopter comprising:

a main rotor with blades;

a helicopter main body having a vibration damping object and configured to rotate said main rotor; and

a vibration reducing apparatus having a vibration damping unit provided to the vibration damping object and a control unit,

wherein said vibration damping unit comprises:

a dynamic mass;

an elastic member configured to apply elastic force to said dynamic mass such that said dynamic mass vibrates in parallel to a vibration damping direction to the vibration damping object;

a control mass;

an actuator coupled to said dynamic mass at a first position of said dynamic mass, to drive said control mass by elongating and contracting in an operation direction of said actuator as a direction of elongation or contraction of said actuator; and

a motion direction converting mechanism configured to couple said control mass to said dynamic mass at a second position of said dynamic mass which is different from the first position and to move said control mass to said dynamic mass into the vibration damping direction through elongation and contraction of said actuator,

wherein said control unit is configured to drive said actuator based on a number of rotations of said main rotor of said helicopter and an acceleration of said helicopter main body, and

wherein said actuator is supported by said dynamic mass such that the operation direction of said actuator is not parallel to the vibration damping direction.

7. The helicopter according to claim 6 , wherein said elastic member and said control mass are arranged such that an elastic member segment as an orthographic projection of said elastic member onto a straight line parallel to the vibration damping direction overlaps with a control mass segment as an orthographic projection of said control mass to the straight line.

8. The helicopter according to claim 6 , wherein said vibration damping unit further comprises a housing which is fixed on the vibration damping object,

wherein said housing comprises:

an upper side member; and

a lower side member disposed to oppose to said upper side member,

wherein said dynamic mass is arranged between said upper side member and said lower side member,

wherein said elastic member comprises:

an upper side elastic member arranged between said upper side member and said dynamic mass; and

a lower side elastic member arranged between said lower side member and said dynamic mass, and

wherein an upper side elastic member junction portion to which said upper side elastic member of said dynamic mass is coupled is arranged to be nearer said lower side member than a lower side elastic member junction portion to which said lower side elastic member of said dynamic mass is coupled.

9. The helicopter according to claim 6 , wherein said vibration damping unit further comprises:

another control mass;

another actuator coupled to said dynamic mass at a third position of said dynamic mass, to drive said another control mass by elongating and contracting in an operation direction of said another actuator; and

another motion direction converting mechanism configured to couple said another control mass to said dynamic mass at a fourth position of said dynamic mass which is different from the first to third positions and to move said control mass to said dynamic mass through elongation and contraction of said another actuator.

10. The helicopter according to claim 6 , wherein said actuator is coupled to said dynamic mass through said motion direction converting mechanism.

11. A vibration reducing method of a helicopter, comprising:

preparing a helicopter which comprises:

a main rotor with blades,

a helicopter main body having a vibration damping object and configured to rotate said main rotor, and

a vibration reducing apparatus having a vibration damping unit provided to the vibration damping object and a control unit;

generating a drive signal based on a number of rotations of said main rotor and an acceleration of said helicopter main body; and

vibration-damping the vibration damping object of said helicopter main body by driving said actuator in response to the drive signal.