Gasket-mounting structure

A combination of a gasket and a fluid device allowing the gasket to be mounted thereon, wherein

• the gasket comprises a first ring including:
• a first axial end having a first slope at an inner periphery;
• a second axial end boated on an opposite side of the first ring from the first axial end;
• and
• a stepwise shape located between outer peripheries of the first axial end and the second axial end to provide the second axial end with an outer diameter larger than an outer diameter of the first axial end;
• the fluid device includes:
• a second slope that, when separated from the first slope, has a gradient different from a gradient of the first slope, and that contacts and presses the first slope such that the gradient of the first slope varies depending on the gradient of the second slope to seal a gap between the first slope and the second slope, and such that the first axial end of the first ring is deformed radially outward to increase an average diameter of the first axial end;
• and
• a convex formed as a sleeve surrounding the second slope, wherein when the first slope contacts and presses the second slope, an inner periphery of a tip end of the convex contacts and presses an outer periphery of the second axial end of the first ring, and due to the stepwise shape of the first ring, the inner periphery of a base end of the convex is radially separated from an outer periphery of the first axial end of the first ring.