| 摘要 |
A gas seal includes a pair of relatively rotatable slide members and a plurality of grooves for generating a hydrodynamic floating force between sliding surfaces of the slide members during rotation are circumferentially formed to one of the slide members so as to extend in a radial direction. A first dam portion for partitioning an inside space in the grooves from an external portion on an outer diameter side of the grooves is formed along an entire peripheral portion of the one of the slide members. Each of the grooves has a V-shaped cross section having a central bottom portion and tapered portions extending from the central bottom portion with inclinations reverse to each other in the circumferential direction thereof and a second dam portion is formed to the bottom portion so as to extend upward. In another aspect of the present invention, a a second dam portion for bilaterally partitioning each of the grooves is formed to a central bottom portion of the groove so as to extend in a radial direction. Each groove has a cross section along the circumferential direction having tapered portions extending from the second dam portion with inclinations reverse to each other and gas flow passages are formed on both sides of the first and second dam portions.
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