A relative movement of a fan 1 toward a motor 2, which is one of
the relative movements of the fan 1 with respect to a rotating shaft 23,
is restricted by an inner ring 221 of a radial bearing 22. Due
to this, the relative movement of the fan 1 toward the motor 2 is
restricted by the inner ring 221 when the joining force between the fan
1 and the rotary shaft 23 is decreased, so that the contact between
the fan 1 and the housing 21 can be prevented. Moreover, as the inner
ring 221 rotates together with the rotating shaft 23, a rotational
force is transferred from the inner ring 221 to the fan 1 in a state
in which the relative movement of the fan 1 toward the motor 2 is
restricted by the inner ring 221.
