Abstract: A brake disk unit includes a rotating member, a brake disk, and a control member. The brake disk includes a disk main body, fins, and convex portions and/or concave portions. The control member includes a support portion and a projecting portion. At least a part of the projecting portion is arranged between fins that are adjacent in the circumferential direction of the brake disk. A gap is formed between the projecting portion and the brake disk. On the surface of the brake disk, the convex portions and/or the concave portions are provided further on the outer side in the radial direction of the brake disk than a minimum opening portion of the gap.

Abstract: An eddy current damper includes a magnet holding member, a first permanent magnet having a thickness (H1), a second permanent magnet having a thickness (H1), a conductive member, a ball nut, a screw shaft, and a copper layer having a thickness (H2). The second permanent magnet is adjacent to the first permanent magnets with a gap therebetween in the circumferential direction of the magnet holding member. The ball nut is fixed to the magnet holding member or the conductive member. The copper layer is fixed to the conductive member and is opposed to the first permanent magnet and the second permanent magnet with a gap therebetween. The thickness (H1) and the thickness (H2) satisfy, with respect to a distance (R1) between a central axis of the screw shaft and the center of gravity of the first permanent magnet: 0.018?H1/R1?0.060, and 0.0013?H2/R1?0.0065.