ROTARY JOINT

PROBLEM TO BE SOLVED: To provide a rotary joint of a metal seal structure hardly causing a galling phenomenon. SOLUTION: A through-hole 11a is bored in a central part in a joint body 11. Bearings 13 and 14 are inserted into both ends of the joint body 11. The bearing 13 is formed in a large diameter in both an inner diameter and an outer diameter. The inner diameter of the bearing 13 is formed in the substantially same as an inside diametral dimension of the through-hole 11a of the joint body 11. An inner diameter of the bearing 14 is formed smaller than an inner diameter of the through-hole 11a. Fluid passages 11d, 11e and 11f are formed on the outer diameter side of the joint body 11 from the inner diameter side of the through-hole 11a between the bearings 13 and 14. A rotary shaft 12 is inserted into the through-hole 11a, and both ends of the rotary shaft 12 are formed into shaft end parts 12a and 12b fitted to the respective inner diameters of the bearings 13 and 14. A shaft intermediate part 12c is formed for constituting the metal seal structure between the through-hole 11a between both shaft end parts 12a and 12b. This shaft intermediate part 12c is formed in a diameter a little smaller than the shaft end part 12a. COPYRIGHT: (C)2006,JPO&NCIPI