ROTARY JOINT

摘要

The present invention includes a mechanical seal that partitions a ring-shaped space formed between a case body and a shaft body. The mechanical seal is provided with a first hermetic seal ring (11) with a first seal surface, a second hermetic seal ring with a second seal surface that is in sliding contact with the first seal surface, and a plurality of coil springs that are disposed circumferentially along the first hermetic seal ring (11) and press the first seal surface against the second seal surface by applying axial-direction force to the first hermetic seal ring (11). The plurality of coil springs are divided into a plurality of groups, and the first hermetic seal ring (11) has first regions (K1) in which the strain produced by the axial-direction force of the coil springs belonging to the groups is large and second regions (K2) in which the strain is smaller than that in the first regions (K1), the first and second regions being present in alternation in the circumferential direction.