Damper device

1 . A damper device comprising:

a first rotator that includes a housing area extending in a circumferential direction and is configured to rotate about a rotation axis;

an intermediate member that includes a common support portion housed in the housing area and is provided so as to be rotatable about the rotation axis relative to the first rotator;

a first seat housed in the housing area and supported by the common support portion;

a second seat housed in the housing area and supported by a first end face surrounding one end of the housing area;

a first elastic body interposed between the first seat and the second seat;

a third seat housed in the housing area and supported by the common support portion, the third seat being disposed such that the common support portion is interposed between the first seat and the third seat;

a fourth seat housed in the housing area and supported by a second end face surrounding the other end of the housing area;

a second elastic body interposed between the third seat and the fourth seat; and

a second rotator that includes a first support portion that supports the second seat and a second support portion that supports the fourth seat, and is provided so as to be rotatable about the rotation axis relative to the first rotator and the intermediate member, wherein at least one target seat out of the first seat, the second seat, the third seat, and the fourth seat is configured to rotate about a fulcrum that is a point at which the at least one target seat abuts against a mating member that supports the at least one target seat so that a second contact surface of the at least one target seat is spaced away from the fulcrum by a second radius larger than a first radius and having a cross section extending in an arc shape slides against a first contact surface of the mating member spaced away from the fulcrum by the first radius and having a cross section extending in an arc shape.

2 . The damper device according to claim 1 , wherein

when the at least one target seat includes the first seat, the mating member that supports the first seat is the common support portion of the intermediate member,

when the at least one target seat includes the second seat, the mating member that supports the second seat is the first end face of the first rotator and/or the first support portion of the second rotator,

when the at least one target seat includes the third seat, the mating member that supports the third seat is the common support portion of the intermediate member, and

when the at least one target seat includes the fourth seat, the mating member that supports the fourth seat is the second end face of the first rotator and/or the second support portion of the second rotator.

3 . The damper device according to claim 2 , wherein a distance between the second contact surface and a rotation center of the damper device is smaller than a distance between the fulcrum and the rotation center.

4 . The damper device according to claim 2 , wherein a distance between an outer edge of the at least one target seat and a rotation center of the damper device is larger than a distance between the fulcrum and the rotation center.

5 . The damper device according to claim 2 , wherein the second contact surface intersects a straight line connecting the fulcrum and a rotation center of the damper device while the at least one target seat rotates about the fulcrum between a first position to be eventually reached by continuing to rotate in a first rotation direction and a second position to be eventually reached by continuing to rotate in a second rotation direction opposite to the first rotation direction.

6 . The damper device according to claim 1 , wherein a distance between the second contact surface and a rotation center of the damper device is smaller than a distance between the fulcrum and the rotation center.

7 . The damper device according to claim 1 , wherein a distance between an outer edge of the at least one target seat and a rotation center of the damper device is larger than a distance between the fulcrum and the rotation center.

8 . The damper device according to claim 1 , wherein the second contact surface intersects a straight line connecting the fulcrum and a rotation center of the damper device while the at least one target seat rotates about the fulcrum between a first position to be eventually reached by continuing to rotate in a first rotation direction and a second position to be eventually reached by continuing to rotate in a second rotation direction opposite to the first rotation direction.