A motor is disclosed. The motor, which includes a stationary member, a rotating member coupled to the stationary member that rotates about an imaginary rotational axis, a plate coupled to or mounted on the rotating member to support the rotating member, a cap covering at least a portion of the plate to form a predetermined space between the plate and the cap, and fluid placed in the space between the plate and the cap, may maintain a uniform pressure in its interior to increase stability and provide an increased sealing effect.