US Patent 7976069 Rotary joint and housing segments of rotary joint

A rotary joint and a housing for a rotary joint include an insertion hole for receiving a rotary shaft, a plurality of housing segments arranged along the shaft, and a housing communicating hole formed in at least one of the housing segments. An annular groove permits communication between the shaft communicating hole and the housing communicating hole. An annular leakage-preventing member between the shaft and the housing blocks fluid movement in an axial direction of the shaft. The shaft includes a cylindrical shaft portion and a small-diameter portion formed at one end. At least one pair of rotating supports support the shaft and the housing. One of the rotating supports is disposed on the small-diameter portion. An outside diameter of one of the rotating supports is smaller than an outside diameter of the shaft and also is smaller than inside diameters of the plurality of housing segments.