Damper apparatus

A damper apparatus comprising:

• a first rotating body that rotates around a rotation axis;
• a second rotating body that rotates relative to the first rotating body around the rotation axis;
• and
• an elastic mechanism unit that includes an elastic body and paired seat members that support both ends of the elastic body, and that elastically connects the first rotating body and the second rotating body in a rotational direction,
• wherein each of the paired seat members includes, on a radially outer end surface, a first surface portion that comes into contact with one of the first rotating body and the second rotating body and a second surface portion that comes into contact with another of the first rotating body and the second rotating body when a twist angle related to the relative rotation of the first rotating body and the second rotating body is 0°,
• when the twist angle is 0°, a first angle θ1 is formed by 1) a first tangent line where the first surface portion comes into contact with the one of the first rotating body and the second rotating body, the first tangent line extending in a direction including a first vector in the rotational direction and a second vector in a direction orthogonal to the rotational direction, and 2) the first vector,
• when the twist angle is 0° and centrifugal force F is generated in the direction orthogonal to the rotational direction, a relationship between frictional force μ1Fcosθ1 acting in a direction opposite to a direction in which the first tangent line extends and first component force Fsinθ1 of the centrifugal force F acting in the direction in which the first tangent line extends satisfies −0.1F≤μ1Fcosθ1−Fsinθ1≤0.1F, where μ1 indicates a first coefficient of friction where the first surface portion comes into contact with the one of the first rotating body and the second rotating body,
• when the twist angle is 0°, a second angle θ2 is formed by 1) a second tangent line where the second surface portion comes into contact with the another of the first rotating body and the second rotating body, the second tangent line extending in a direction including a third vector in the rotational direction and a fourth vector in a direction orthogonal to the rotational direction, and 2) the third vector, and
• when the twist angle is 0° and the centrifugal force F is generated in the direction orthogonal to the rotational direction, a relationship between frictional force μ2Fcosθ2 acting in a direction opposite to a direction in which the second tangent line extends and second component force Fsinθ2 of the centrifugal force F acting in the direction in which the second tangent line extends satisfies −0.1F≤μ2Fcosθ2−Fsinθ2≤0.1F, where μ2 indicates a second coefficient of friction where the second surface portion comes into contact with the another of the first rotating body and the second rotating body.