A damper device includes first inner springs configured to transmit a torque between a drive member and an intermediate member, second inner springs configured to transmit a torque between the intermediate member and a driven member, and a rotary inertia mass damper including a sun gear serving as a mass body rotating with relative rotation of the drive member to the driven member. The rotary inertia mass damper is provided in parallel to a torque transmission path including the intermediate member, the first inner springs and the second inner springs. A damping ratio of the intermediate member determined based on a moment of inertia J.sub.2 of the intermediate member and rigidities k.sub.1 and k.sub.2 of the first and the second inner springs and is less than a value.

A damper apparatus includes an input element, an output element, a first intermediate element, a second intermediate element, a first elastic body configured to transfer the torque between the input and first intermediate elements, a second elastic body configured to transfer the torque between the first intermediate and output elements, a third elastic body, a fourth elastic body configured to transfer the torque between the second intermediate element and the output element, and a fifth elastic body configured to transfer the torque between the first intermediate element and the second intermediate element. At least one of the first and second intermediate elements includes a single member on which a first torque transfer portion disposed between the first and second elastic bodies or between the third and fourth elastic bodies and a second torque transfer portion configured to exchange the torque with the fifth elastic body are both formed.

A damper apparatus includes a first rotating body, a second rotating body, and an elastic mechanism unit including an elastic body and paired seat members. The seat member includes a first surface portion coming into contact with one of the first rotating body and the second rotating body and a second surface portion coming into contact with another of the first rotating body and the second rotating body, a first angle ?1 formed by a first tangent line at a first point of contact, the first tangent line including a first vector and a second vector, and the first vector is 11.5???1?22.0?, and a second angle ?2 formed by a second tangent line at a second point of contact, the second tangent line including a third vector and a fourth vector, and the third vector is 11.5???2?22.0?.

A dynamic damper is coupled to an intermediate member of a damper device. A drive member of the damper device has additional abutment portions coupled to end portions of vibration absorption springs of the dynamic damper before both first and second inter-element stoppers operate. The second inter-element stoppers operate before the first inter-element stoppers operate and at least by the time when the additional coupling portions are coupled to end portions of the vibration absorption springs. Outer springs and the vibration absorption springs act in parallel to transfer torque after the additional coupling portions are coupled to end portions of the vibration absorption springs.

A lock-up device for a torque converter for transmitting a torque and for absorbing and attenuating a torsional vibration includes an input rotary member, an output rotary member disposed on both axial sides of the input rotary member and rotatable relatively to the input rotary member, and a plurality of first coil springs disposed in radially inner positions. The first coil springs are compressed in series by rotation of the input rotary member relative to the output rotary member whereby the torque is inputted therein from the input rotary member. The lock-up device also includes at least one second coil spring compressed when the input rotary member and the output rotary member are rotated relatively to each other at a predetermined relative angle or greater. The lock-up device additionally includes a float member disposed radially inward of the first coil springs and coupling the plural first coil springs in series.

A torque transmission apparatus including an intermediate member disposed in a power transmission path between a first rotor and second rotor; a first elastic member interposed between the first rotor and the intermediate member; a second elastic member interposed between the intermediate member and the second rotor; and an inertial body connected to the intermediate member through a third elastic member. The third elastic member is placed between the first elastic member and the second elastic member in an axial direction and between the first elastic member and the second elastic member in a radial direction.

A torque transmission apparatus including an intermediate member disposed in a power transmission path between a first rotor and second rotor; a first elastic member interposed between the first rotor and the intermediate member; a second elastic member interposed between the intermediate member and the second rotor; an inertial body connected to the intermediate member through a third elastic member; and an elastic member supporter supporting the third elastic member to be expandable and contractible. The elastic member supporter supports the third elastic member in a manner of applying an initial load to the third elastic member, in an initial state of the first and second rotors being non-rotating.

A hydrokinetic torque coupling device comprising an impeller wheel (2) able to hydrokinetically drive a turbine wheel (3) into rotation, with the impeller wheel (2) being rotationally coupled to a cover (5), with the turbine wheel (3) being able to be axially moved between an engaged position and a disengaged position, wherein it comprises an elastically deformable stress overtaking member (25) axially inserted between the turbine wheel (3) and a part (12) of the cover (5), with the stress overtaking member (25) being able to limit the axial displacement of the turbine wheel (3) towards the above-mentioned part (12) of the cover (5), opposite the turbine wheel (3).

In an aspect, an isolator is provided, comprising a hub, a pulley, an isolation spring and a transition spring. The hub defines an axis and is connectable to a rotatable shaft of a rotary device. The pulley is rotatably mounted to the hub. The isolation spring and transition spring act in series in a torque path between the pulley and the hub. The isolation spring has a first spring rate. The transition spring has a second spring rate that is lower than the first spring rate.

A damper device that includes an input to which torque from an engine is transmitted; an output; a first intermediate element; a second intermediate element; a first elastic body disposed between the input and the first intermediate element; a second elastic body disposed between the first intermediate element and the output; a third elastic body disposed between the input and the second intermediate element; a fourth elastic body disposed between the second intermediate element and the output; and a fifth elastic body disposed between the first intermediate element and the second intermediate element, wherein at least one of the first to fifth elastic bodies has negative rigidity.