To enhance damping effect on vibrations transmitted from a rotor to a housing.

A damping mechanism 50 comprises an inner ring 51, an outer ring 52, a spring plate 53, and a thrust stopper 55. A base portion 51a of the inner ring 51 and an inner peripheral portion 61 of the outer ring 52 axially have a gap h₁ between them, and an outer peripheral portion 62 of the outer ring 52 and the spring plate 53 have a gap h₂ between them. The gap h₁ is smaller than an elastic deformation limit ε_Z of the spring plate 53, and the gap h₂ is larger than the gap h₁. An outer peripheral surface of the base portion 51a of the inner ring 51 and an inner peripheral surface 62a of the outer peripheral portion 62 of the outer ring 52 radially have a gap r₁ therebetween that is smaller than the elastic deformation limit ε_Z of the spring plate 53.