Vibration damping device

1. A vibration damping device, comprising:

a holding member that is fitted onto a rotary member to suppress torsional vibrations on the rotary member while expanding radially outwardly;

a rolling mass that is held in the holding member while being allowed to oscillate in a rotational direction of the rotary member; and

a cover member that covers an oscillating range of the rolling mass liquid-tightly or air-tightly;

wherein the cover member includes a protrusion covering the oscillating range of the rolling mass in an oscillatable manner, a first flange that extends from the protrusion toward an inner circumferential side of the oscillating range on one of lateral faces of the holding member through a first sealing member, and a second flange that extends from the protrusion toward the inner circumferential side of the oscillating range on the other lateral face of the holding member through a second sealing member;

the vibration damping device further comprising:

a first pushing member that is fitted onto the rotary member while being prevented to move in an axial direction to push the first flange toward said one of lateral faces of the holding member to compress the first sealing member between the first flange and the holding member;

a second pushing member that is fitted onto the rotary member while being prevented to move in the axial direction to push the second flange toward the other lateral face of the holding member to compress the second sealing member between the second flange and the holding member;

a fluid coupling that hydraulically transmits an output torque of a prime mover to the rotary member; and

a lockup clutch that transmits the output torque of the prime mover to the rotary member without the fluid coupling when it is engaged with an input member of the fluid coupling;

wherein the first pushing member includes a first connection member that transmits the output torque of the prime mover through the lockup clutch; and

wherein the second pushing member includes a second connection member that transmits the output torque of the prime mover through the fluid coupling.

2. The vibration damping device as claimed in claim 1 , wherein the holding member is disposed between the first pushing member and the second pushing member.

3. The vibration damping device as claimed in claim 1 ,

wherein any one of the first pushing member and the second pushing member is integrated with the rotary member,

wherein the vibration damping device further comprises a positioning member that fixes a position of an end face of any one of the other first pushing member and second pushing member opposite to a face thereof opposed to said one of the first pushing member and the second pushing member, and

wherein the first flange is pushed by the first pushing member and the second flange is pushed by the second pushing member by fixing the position of the end face of said any one of the other first pushing member and second pushing member.

4. The vibration damping device as claimed in claim 1 ,

wherein the first pushing member is adapted to push the first flange at a level where the first sealing member is situated, and

wherein the second pushing member is adapted to push the second flange at a level where the second sealing member is situated.

5. A vibration damping device, comprising:

a holding member that is fitted onto a rotary member to suppress torsional vibrations on the rotary member while expanding radially outwardly;

a rolling mass that is held in the holding member while being allowed to oscillate in a rotational direction of the rotary member; and

a cover member that covers an oscillating range of the rolling mass liquid-tightly or air-tightly;

wherein the cover member includes a protrusion covering the oscillating range of the rolling mass in an oscillatable manner, a first flange that extends from the protrusion toward an inner circumferential side of the oscillating range on one of lateral faces of the holding member through a first sealing member, and a second flange that extends from the protrusion toward the inner circumferential side of the oscillating range on the other lateral face of the holding member through a second sealing member;

the vibration damping device further comprising:

a first pushing member that is fitted onto the rotary member while being prevented to move in an axial direction to push the first flange toward said one of lateral faces of the holding member to compress the first sealing member between the first flange and the holding member; and

a second pushing member that is fitted onto the rotary member while being prevented to move in the axial direction to push the second flange toward the other lateral face of the holding member to compress the second sealing member between the second flange and the holding member;

wherein the first pushing member is adapted to push the first flange at a level where the first sealing member is situated, and

wherein the second pushing member is adapted to push the second flange at a level where the second sealing member is situated.

6. The vibration damping device as claimed in claim 5 , wherein the holding member is disposed between the first pushing member and the second pushing member.

7. The vibration damping device as claimed in claim 5 ,

wherein any one of the first pushing member and the second pushing member integrated with the rotary member,

wherein the vibration damping device further comprises a positioning member that fixes a position of an end face of any one of the other first pushing member and second pushing member opposite to a face thereof opposed to said one of the first pushing member and the second pushing member, and

wherein the first flange is pushed by the first pushing member and the second flange is pushed by the second pushing member by fixing the position of the end face of said any one of the other first pushing member and second pushing member.