Patent ID: 7037126

Claim:
A rotary joint comprising: a stator; a rotor rotatably coupled to and supported by the stator; an electric slip ring that has electrodes mounted to the stator and the rotor and passes electricity between the electrodes, and a swivel joint for communicating fluid between the stator and the rotor, wherein the electric slip ring is concentrically arranged at a distance further than the swivel joint from the rotational axis of the rotor, such that the electric slip ring overlaps the swivel joint when viewed from a direction orthogonal to the rotational axis, an annular space, formed between a portion of the stator and a portion of the rotor and adjacent to the swivel joint, to accommodate the electric slip ring, wherein the center of the electric slip ring is at the rotational axis of the rotor, wherein the swivel joint has a single or more of annular passages formed in axially aligned relation between the stator and rotor and extending circumferentially, and through which the fluid flows, and an annular space filled with air flowing to and from the exterior is disposed in a position to block flow of fluid into the region of the electric slip ring between the single or group of annular passages and the annular space for the electric slip ring.