US Patent 7914209 Bearing seal and swing device

A bearing seal includes an outer seal easily displaceable in the radial direction, an inner ring as a ring-shaped rigid portion not extendable in the radial direction, an inner seal having a seal lip, and an outer ring arranged on the outer peripheral portion of the outer seal, in which the spring constant of the inner seal is set to be larger than the spring constant of the outer seal. The sealing performance between the inner seal and the pin is ensured by using the ring-shaped rigid portion as a boundary. When the pin is displaced in the radial direction, the ring-shaped rigid portion is integrally displaced with the pin via the inner seal, and the displacement of the ring-shaped rigid portion can be absorbed by the outer seal.